Cover of Laboratory Tests and Diagnostic Procedures
Laboratory Tests and Diagnostic Procedures
Sixth Edition
Copyright © 2013, 2008, 2004, 2001, 1997, 1993 by Saunders, an imprint of Elsevier Inc.
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Buy your copy at Elsevier Health Bookstore today
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BOOK CHAPTER
A
Cynthia C. Chernecky PhD, RN, CNS, AOCN, FAAN and Barbara J. Berger MSN, RN, CNS
Laboratory Tests and Diagnostic Procedures , 84-180
Open reading mode
3-D Body Scan See Dual Modality Imaging—Diagnostic. Abeta42 See Beta-Amyloid Protein—CSF. Abdominal Aorta Ultrasonography (Abdominal Aorta Echogram, Abdominal Aorta Ultrasound)— Diagnostic Norm. Negative for presence of aneurysm. Normal cross-sec...
3-D Body Scan
See Dual Modality Imaging—Diagnostic .
Aβ 42
See Beta-Amyloid Protein—CSF .
Abdominal Aorta Ultrasonography (Abdominal Aorta Echogram, Abdominal Aorta Ultrasound)— Diagnostic
Norm.
Negative for presence of aneurysm. Normal cross-sectional diameter of adult aorta (maximum internal diameter) varies from 3 cm at the xiphoid to about 1 cm at the bifurcation. Transverse and vertical diameters should be the same. Measurements should be taken at various points down the length of the aorta. Any significant increase in diameter toward the feet (caudally) is abnormal. Ultrasound underestimates the anteroposterior diameter (mean, 2.16 mm) and transverse diameter (mean, 4.29 mm) of the abdominal aorta.
Usage.
Localization, measurement, and monitoring of abdominal aortic aneurysm; follow-up evaluation of surgical graft and aortic attachment after surgery for aneurysm; and detection of abdominal aortic atherosclerosis or thrombus. May be indicated in clients with pulsatile abdominal mass, poor circulation of the legs, recent abdominal trauma, and suspected idiopathic aortitis.
Description.
Evaluation of the structure, size, and position of the abdominal aorta and branches (celiac trunk and renal, superior mesenteric, and common iliac arteries) by the creation of an oscilloscopic picture from the echoes of high-frequency sound waves passing over the anterior portion of the trunk (acoustic imaging). The time required for the ultrasonic beam to be reflected back to the transducer from differing densities of tissue is converted by a computer to an electrical impulse displayed on an oscilloscopic screen to create a three-dimensional picture of the abdominal aorta and branches. Ultrasonography allows measurement of the luminal diameter of the aorta. A narrowed lumen would indicate atherosclerosis or thrombus, whereas a wider-than-normal lumen with an irregular border may indicate aneurysm. Scattered internal echoes within the aneurysm may indicate an internal clot. A double lumen may indicate a tear in the wall of the abdominal aorta. Surgical grafts from aneurysm repair appear as bright echo reflections.
Professional Considerations
Consent form NOT required.
Preparation
1. This test should be performed before intestinal barium tests or else after the barium is cleared from the system (with allowance of several days for clearance).
2. An enema may be prescribed to be given before the ultrasonogram is taken.
3. The client should wear a gown.
4. Obtain ultrasonic gel or paste.
Procedure
1. Client is positioned supine on a procedure table.
2. The abdomen is covered with conductive gel.
3. A lubricated transducer is passed slowly along the abdomen at 1-cm intervals along the transverse and then longitudinal lines, covering the area between the xiphoid process and the symphysis pubis. If dissection is suspected, real-time techniques can be used more specifically to locate the site.
4. Photographs are taken of the oscilloscopic images.
5. Procedure takes less than 60 minutes.
Postprocedure Care
1. Cleanse skin of ultrasonic gel.
Client and Family Teaching
1. Eat a low-residue diet the day before the ultrasonogram is taken, fast from food and fluids after midnight before the test, and refrain from smoking.
2. Lie as still as possible during the procedure, which is painless and carries no risks.
3. Results are normally available within 24 hours.
Factors That Affect Results
1. Dehydration interferes with adequate contrast between organs and body fluids.
2. Intestinal barium or gas obscures results by preventing proper transmission and deflection of the high-frequency sound waves.
3. The more abdominal fat present, the greater is the attenuation (reduction in sound-wave amplitude and intensity), which interferes with the clarity of the picture.
4. Aorta may be displaced by scoliosis, a retroperitoneal mass, or the para-aortic lymph nodes; in some clients, these anomalies can mimic an aneurysm.
Other Data
1. There is some evidence that aneurysms smaller than 4 cm in diameter may be safely followed by ongoing monitoring and any aneurysm larger than 4 cm in diameter should be considered for surgery.
2. Ultrasound ranks below CAT scan (or CT scan) in its accuracy; however, it surpasses CT in screening.
Abdominal Plain Film
See Flat-Plate Radiography of Abdomen—Diagnostic .
Abdominal Ultrasound
See Abdominal Aorta Ultrasonography—Diagnostic ; Gallbladder and Biliary System Ultrasonography—Diagnostic ; Liver Ultrasonography—Diagnostic ; Obstetric Ultrasonography—Diagnostic ; Pancreas Ultrasonography—Diagnostic ; and Spleen Ultrasonography—Diagnostic .
Abeta
See Beta-Amyloid Protein—CSF .
ABG
See Blood Gases, Arterial—Blood .
ABI
See Ankle-Brachial Index—Diagnostic .
ABO Group and Rh Type— Blood
Norm.
Specific to each individual.
Usage.
Blood transfusion therapy, erythroblastosis fetalis, paternity determinations, pregnancy, and preoperatively.
Description.
The ABO blood group is the phenotype of a client's blood resulting from genetic inheritance. The four most common phenotypes are A, B, AB, and O, referring to the type of antigen present on the surface of red blood cells. Rh type refers to whether an Rh antigen is present (Rh positive) or absent (Rh negative) on the surface of a client's red blood cells. Routine testing usually involves only the Rh 0 (D) antigen. If an Rh-negative client receives Rh-positive blood, he or she will develop Rh antibodies, and future Rh-positive transfusions may cause a transfusion reaction. In pregnancy, antibodies from an Rh-negative mother may hemolyze fetal erythrocytes in a fetus that has inherited the Rh-positive antigen from the father (erythroblastosis fetalis, or hemolytic disease of the newborn). This test determines the specific ABO phenotype and Rh type by determining which A and B red blood cell antigens are present as well as whether the Rh 0 (D) antigen is present.
Professional Considerations
Consent form NOT required.
Preparation
1. Assess client for history of recent blood transfusion reaction, which can result in a positive antibody screen and require further testing. Write affirmative history on blood bank requisition.
2. Tube: Red topped, red/gray topped, or gold topped, 1 or 2 tubes.
Procedure
1. Ask the client to state full name and compare with the client's name band. Label the sample tube and laboratory requisition with the client's name, identification number, date, time, and initials and sign it. Some institutions require additional data.
2. Draw one or two 10-mL blood samples, depending on institutional requirements.
Postprocedure Care
1. Some institutions require application of a blood band to the client's wrist. The blood bank identification numbers should match the identification numbers on any blood bag used for transfusion for the client.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Hemolyzed specimen invalidates results.
2. Specimen drawn from extremity into which blood or dextran is infusing invalidates results.
3. Drugs causing a false-positive Rh test include levodopa, methyldopa, and methyldopate hydrochloride.
4. Abnormal plasma proteins, cold autoagglutinins, positive direct antiglobulin test, and in some cases, bacteremia may interfere with results.
Other Data
1. The test must be performed within 48 hours of specimen collection.
2. Amerindians are blood group O. Incompatible platelet products that are transfused can cause acute intravascular hemolysis.
3. ABO incompatibility is a significant prognostic risk factor in allogeneic bone marrow transplant for acute myelogenous leukemia or myelodysplastic syndrome.
4. See also Type-and-crossmatch, Blood .
Abscess
See Body Fluid—Anaerobic Culture .
ACA
See Antiphospholipid Antibodies—Serum .
Accu-Chek
See Glucose Monitoring Machines—Diagnostic .
ACE
See Angiotensin-Converting Enzyme—Blood .
Acetaminophen— Serum
Norm.
2 months to 10 years (received >60 mg of APAP/kg/day) = 0-23 mg/mL.
4 Hours After Last Dose SI Units
Therapeutic level 10-30 µg/mL 66-199 µmol/L
Toxic level >150 µg/mL >990 µmol/L
Panic level (hepatotoxicity) >200 µg/mL >1320 µmol/L View full size
APAP, N -acetyl- p -aminophenol.
Overdose Symptoms and Treatment
Symptoms.
Occur in four stages.
1. Stage I (ingestion to 24 hours): Gastrointestinal irritation, pallor, lethargy, diaphoresis, metabolic acidosis, and coma (cases of massive ingestion with serum concentration >800 µg/mL have been reported, but coma is usually attributed to a coingestant such as alcohol).
2. Stage II (24 to 48 hours): Increased serum hepatic enzymes, right upper quadrant abdominal pain, possible decreased renal function.
3. Stage III (72 to 96 hours): Increased AST, increased ALT, nausea, vomiting, jaundice, lethargy, confusion, coma, coagulation disorders, possible decreased renal function.
4. Stage IV (4 days to 2 weeks): Clinical symptoms subside; laboratory values return to baseline.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Establish and maintain adequate airway, respiratory, and circulatory function.
2. If client is obtunded or unconscious, appropriate doses of thiamine, dextrose, and naloxone must be considered.
3. Gastric decontamination: In one study, rapid complete bowel lavage with 4 g of polyethylene glycol electrolyte solution was shown to significantly reduce serum acetaminophen levels. In another study, use of activated charcoal prevented acetaminophen absorption when given within 60 minutes of acetaminophen ingestion. An emetic may be used to induce emesis for recent ingestion, but it must be used with extreme caution. Ondansetron can be used to manage vomiting if acetaminophen ingestion occurred within the previous 8 hours.
4. Oral administration of N -acetylcysteine (Mucomyst by Mead Johnson) for suspected toxic doses (>7.5 g). Mucomyst is most likely to be effective when given within 16 hours after acetaminophen ingestion.
5. Laboratory monitoring: Urine toxicology screen, hepatic profile daily for 3-4 days, BUN, Cr, serum electrolytes, serum acetaminophen concentration level 4 hours after ingestion.
6. Coingestion of other substances that delay gastric emptying is an indication for serial measurement to detect late-rising acetaminophen levels.
7. Chronic alcohol intake enhances acetaminophen hepatotoxicity.
8. Hemodialysis WILL but peritoneal dialysis will NOT remove acetaminophen.
Usage.
Drug abuse, hepatitis, monitoring for toxicity during acetaminophen therapy, overdose, poisoning, and suicide.
Description.
Acetaminophen (also known as paracetamol) is a p -aminophenol derivative that has antipyretic (direct action on hypothalamus) and moderate analgesic actions. It is absorbed by the gastrointestinal tract and metabolized by liver microsomes. Half-life is 1 to 4 hours with peak blood levels reached in 30 minutes to 1 hour. Used for headache, fever, and relief of pain in clients who cannot tolerate aspirin or those with peptic ulcers or bleeding disorders. It is the drug of choice (antipyretic/analgesic) in children 13 years of age and younger because of the possible development of Reye's syndrome associated with aspirin. In adults, ingestion of more than 4 g/day can be hepatotoxic.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, gold topped, or lavender topped.
2. Do NOT draw during hemodialysis.
3. Document times of ingestion and sample collection on lab requisition.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 24 hours.
2. If overdose is suspected, prepare client and family for necessary supportive treatment described above.
3. If activated charcoal was given for elevated levels, client should drink 4 to 6 glasses of water each day for 2 days to prevent constipation. Activated charcoal will also cause stools to be black for a few days.
Factors That Affect Results
1. Cardiovascular, hepatic, gastrointestinal, or renal dysfunction can alter drug absorption and elimination.
2. Toxic levels of acetaminophen positively interfere with glucose-monitoring machine results.
3. Draw two samples, 4 hours apart, to determine the half-life of acetaminophen.
Other Data
1. Acetaminophen is present in many medicines: Anacin 3, Datril, Liquiprin, Panadol, Panex, paracetamol, Phenaphen, Tempra, and Tylenol.
2. Acetaminophen used with aspirin and caffeine alleviates migraine headache pain.
3. Premedication with acetaminophen does not significantly lower the incidence of nonhemolytic transfusion reactions.
4. Acetaminophen poisoning has been found in nearly 50% of all acute liver failure in the United States.
5. Prothrombin time prolongation may be noted in clients with hepatic failure and paracetamol poisoning.
Acetone
See Acetone—Urine ; Ketone Bodies—Blood or Toxicology; Volatiles Group by GLC—Blood or Urine .
Acetone— Urine
Norm.
Keto-Diastix or Multistix: Negative. Quantitative 0.3-2.0 mg/dL.
Usage.
Differentiation of diabetic coma and insulin shock, evaluation of glucose control in diabetics, preadmission screening, pregnancy, screening for ketoacidosis, and monitoring for occupational exposure to isopropyl alcohol. Increased in ethanol hangover and in ingestion of denatured alcohol.
Description.
Acetone is a by-product of fat and fatty acid metabolism that provides a source of cellular energy for cells when glucose stores are exhausted or when glucose is prevented from entering cells because of lack of insulin. Acetone entering the bloodstream is almost completely metabolized in the liver. When acetone is formed at a faster-than-normal rate or is present in the bloodstream in higher-than-normal levels, it is excreted in the urine.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a clean urine container and acetone testing strips or tablets.
2. Client should empty the bladder 30 minutes before specimen collection and then drink a glass of water.
3. For specimens obtained from an indwelling urinary catheter, also obtain a catheter clamp, a sterile 10-mL syringe and needle, and an alcohol wipe.
Procedure
1. Obtain a 20-mL double-voided urine specimen in a clean container.
2. Specimens from catheter: Clamp the catheter tubing for 15 minutes to allow urine to accumulate above the sample port. Cleanse the sample port with an alcohol wipe and allow to dry. Aspirate 20 mL of urine from the sample port, using a sterile syringe and needle. Collect only fresh urine that has accumulated above the sample port. Unclamp the catheter tubing.
3. Dip the Keto-Diastix, Multistix, or other acetone testing material in fresh urine and hold the strip horizontally for 15 seconds.
4. Compare the color of the ketone patch on the strip with the color chart on the container of acetone testing strips.
5. Alternative method using Acetest tablets: Place a drop of urine on an Acetest tablet and wait 30 seconds. Compare the color with the Acetest color chart.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are immediately available.
Factors That Affect Results
1. Fasting or dieting may cause acetone to appear in the urine.
2. Use of acetone tablets that are darkened or expired invalidates results.
3. Drugs that may cause false-positive results include captopril, levodopa, paraldehyde, and phenazopyridine hydrochloride.
4. Gender and ingestion of alcohol may affect the basal levels of urinary acetone.
Other Data
1. Refrigerate the specimen if the test cannot be performed within 1 hour of collection.
2. In one study, ratings on scales of well-being and acute symptoms correlated significantly with the concentration of acetone in urine after acute airborne acetone exposure.
3. See also Ketone, semiquantitative—Urine .
Acetylcholine Receptor Antibody— Serum
Norm.
≤ 0.03 nmol/L.
Usage.
Diagnosis and clinical monitoring of myasthenia gravis, Lambert-Eaton myasthenic syndrome, small cell lung carcinoma.
Description.
In clients with myasthenia gravis, this antibody interferes with the binding of acetylcholine to receptor sites on the muscle membrane, thus preventing muscle contraction. Assays for acetylcholine receptor (AChR) antibodies are positive in 85%-90% of clients with acute myasthenia gravis and are replacing the Tensilon test as a diagnostic aid for this condition. However, this assay is less sensitive for Lambert-Eaton myasthenic syndrome diagnosis.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List on the laboratory requisition any recent immunosuppressive drug therapy the client received.
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results may not be available for several days.
Factors That Affect Results
1. False-positive results may be caused by D-penicillamine.
2. Decrease in titer may be caused by intravenous immunoglobulin (IVIg) therapy.
3. Clients with orthostatic hypotension may have a seropositive AChR antibody.
Other Data
1. Undetectable titer occurs in 33.4% of clients who have only ocular myasthenia gravis.
2. See also Tensilon test—Diagnostic .
Acetylsalicylic Acid
See Salicylate—Blood .
ACG— Diagnostic
See Apexcardiography—Diagnostic .
Acid-Fast Bacteria— Culture and Stain
Norm.
Negative.
Usage.
Acquired immune deficiency syndrome (AIDS); suspected Helicobacter pylori , intestinal parasites, leprosy, mycobacteriosis, or tuberculosis; and differentiation of tuberculosis from carcinoma and bronchiectasis.
Description.
Mycobacterium tuberculosis is a rod-shaped bacterium that resists decolorizing chemicals after staining, a property termed “acid-fastness .” M. tuberculosis is transmitted most commonly by the airborne route to the lungs, where it survives well, causes areas of granulomatous inflammation, and, if not dormant, causes cough, fever, and hemoptysis. The acid-fast bacterium Mycobacterium avium-intracellulare is a common cause of infection in clients with AIDS. Culture of sputum is necessary to confirm the diagnosis of tuberculosis and for sensitivity studies for drug therapy. The sensitivity of sputum smears for tuberculosis, however, is only 50%. The CDC recommends that every client with suspected tuberculosis also have nucleic acid amplification testing performed on at least one respiratory specimen. Nucleic acid amplification testing provides earlier confirmation (24-48 hours) of tuberculosis than does culture.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain three small, sterile containers.
2. See Client and Family Teaching .
Procedure
1. Aerosolized therapy before sputum collection may stimulate sputum production and produce a better specimen.
2. When tuberculosis is suspected, collect three daily, early-morning sputum, deep-cough specimens in a sterile container.
3. When leprosy is suspected, obtain smear from nasal scrapings or biopsy from lesions and place in sterile container.
Postprocedure Care
1. Provide mouth care.
Client and Family Teaching
1. Perform oral hygiene before giving specimens to reduce chances of contamination.
2. Deep coughs are necessary to produce sputum, rather than saliva. To produce the proper specimen, take several breaths in, without fully exhaling each, and then expel sputum with a “cascade cough.”
Factors That Affect Results
1. Antituberculous drug therapy may cause negative results because of inhibition of growth of M. tuberculosis .
2. A high–carbon dioxide atmosphere for growth may increase the number of positive cultures.
3. Culture medium containing glycerin accelerates growth.
Other Data
1. Culture results may take 3-8 weeks.
2. The most prevalent intestinal parasites in cancer clients diagnosed by acid-fast stain are Entamoeba histolytica/Entamoeba dispar (8.5%), Giardia lamblia (3.1%), Strongyloides stercoralis (0.6%), and Cryptosporidium parvum (0.3%).
Acid-Fast Stain, Nocardia Species— Culture
Norm.
Negative.
Usage.
Aids in diagnosis of Behçet's disease, mycetoma, Nocardia brasiliensis , and nocardiosis of the respiratory tract found in persons with systemic lupus erythematosus and nocardial thyroiditis.
Description.
Nocardia is an aerobic, gram-positive, filamentous branching bacterium that segments into reproductive bacillary fragments. It is weakly acid fast; found outdoors in decayed matter, soil, grass, and straw; and enters the body primarily through inhalation of contaminated dust. The type species, Nocardia asteroides , and N. brasiliensis, N. farcinica, N. otitidis-caviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The N. asteroides species causes primary skin lesions, visceral infections (most commonly abscesses of the lungs, brain, and subcutaneous tissue), and sometimes disseminated infections in humans.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a sterile scalpel or spatula, or a sterile needle and syringe, and both anaerobic and aerobic culture media.
Procedure
1. Obtain a scraping from a skin lesion or an aspirate of an abscess using sterile technique.
2. Inoculate both aerobic and anaerobic culture media with the specimen.
3. Aerobic culture media of beef infusion broth or thioglycolate broth may be used.
4. Initial incubation at temperatures from 38 to 45 degrees C should be used.
5. Examine cultures for growth beginning at 48 hours and recheck daily for 2 weeks.
Postprocedure Care
1. Apply dry sterile dressing to site.
Client and Family Teaching
1. Avoid application of creams or lotions to sample site and allow site to remain open to air for healing.
2. At least 2-3 days are required for growth and results.
Factors That Affect Results
1. Nocardia growth may be mistaken for nontuberculous Mycobacterium when a Mycobacterium culture medium is used.
Other Data
1. Common specimens include pus, tissue, body fluid, and sputum.
2. Final reports may take 10 days.
Acid Hemolysin Test— Blood
See Ham's Test—Blood .
Acidified Serum Test— Blood
See Ham's Test—Blood .
Acid Phosphatase— Serum
Norm.
Method SI Units
Bodansky 0.5-2 U/L 2.7-10.7 IU/L
King-Armstrong 0.1-5 U/L 0.2-8.8 IU/L
Bessey-Lowery-Brock 0.1-0.8 U/L 1.7-13.4 IU/L
Gutman 0.1-2 U/L View full size
Increased.
Bone fracture, cancer with bone metastasis, Gaucher disease, hairy cell leukemia (leukemic reticuloendotheliosis), hepatitis (viral), hyperparathyroidism, hypophosphatemia, idiopathic thrombocytopenic purpura (with bone marrow megakaryocytes), jaundice (obstructive), Laënnec's cirrhosis, leukemia (myelogenous), multiple myeloma, osteogenesis imperfecta, Paget's disease (advanced), partial translocation trisomy 21, prostate cancer, prostatic infarction, prostatic surgery or trauma, renal impairment (acute), sickle cell crisis, thrombocythemia, thrombocytosis, thromboembolism, and thrombophlebitis. Drugs include anabolic steroids.
Decreased.
No clinical significance. Drugs include fluorides.
Description.
Acid phosphatase is one of a group of enzymes located primarily in the prostate gland and prostatic secretions. Smaller amounts are found in the bone marrow, spleen, liver, kidneys, and blood components such as erythrocytes and platelets. Isoenzymes of acid phosphatase include prostatic isoenzyme and erythrocytic isoenzyme. Used in diagnosis of and monitoring for treatment response of prostate cancer.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Collect a 4-mL blood sample.
Postprocedure Care
1. Send the specimen to the laboratory immediately.
2. Separate the serum, add 0.01 mL of 20% acetic acid per milliliter of serum, and refrigerate if the test is not performed immediately.
Client and Family Teaching
1. Results may not be available for several days.
Factors That Affect Results
1. Hemolysis or specimens received more than 15 minutes after collection invalidate results.
2. False-negative results may be attributable to use of a collecting tube containing fluorides, oxalates, or phosphates.
3. Drugs that cause false-positive results include clofibrate.
4. Elevated levels may be caused by rectal examination, prostatic massage, or urinary catheterization within 2 days before the test.
Other Data
1. This test is more helpful for diagnosis in advanced prostate cancer than in early prostate cancer.
2. Use of prostate-specific acid phosphatase as a tumor marker for prostate cancer is being replaced by Prostate-specific antigen—Serum.
3. See also Prostatic acid phosphatase—Blood .
Acid Phosphatase, Tartrate-Resistant— Blood
See Tartrate-Resistant Acid Phosphatase Stain—Specimen .
Acid Phosphatase— Vaginal Swab
Norm.
Method: Dilution with a substrate of thymolphthalein monophosphate.
<5 span="" style="white-space: pre;">
Normal vaginal secretions<7 span="" style="white-space: pre;"> Laboratory Tests and Diagnostic Procedures
Sixth Edition
Copyright © 2013, 2008, 2004, 2001, 1997, 1993 by Saunders, an imprint of Elsevier Inc.
Want to own this book?
Buy your copy at Elsevier Health Bookstore today
Get rights and content
BOOK CHAPTER
A
Cynthia C. Chernecky PhD, RN, CNS, AOCN, FAAN and Barbara J. Berger MSN, RN, CNS
Laboratory Tests and Diagnostic Procedures , 84-180
Open reading mode
3-D Body Scan See Dual Modality Imaging—Diagnostic. Abeta42 See Beta-Amyloid Protein—CSF. Abdominal Aorta Ultrasonography (Abdominal Aorta Echogram, Abdominal Aorta Ultrasound)— Diagnostic Norm. Negative for presence of aneurysm. Normal cross-sec...
3-D Body Scan
See Dual Modality Imaging—Diagnostic .
Aβ 42
See Beta-Amyloid Protein—CSF .
Abdominal Aorta Ultrasonography (Abdominal Aorta Echogram, Abdominal Aorta Ultrasound)— Diagnostic
Norm.
Negative for presence of aneurysm. Normal cross-sectional diameter of adult aorta (maximum internal diameter) varies from 3 cm at the xiphoid to about 1 cm at the bifurcation. Transverse and vertical diameters should be the same. Measurements should be taken at various points down the length of the aorta. Any significant increase in diameter toward the feet (caudally) is abnormal. Ultrasound underestimates the anteroposterior diameter (mean, 2.16 mm) and transverse diameter (mean, 4.29 mm) of the abdominal aorta.
Usage.
Localization, measurement, and monitoring of abdominal aortic aneurysm; follow-up evaluation of surgical graft and aortic attachment after surgery for aneurysm; and detection of abdominal aortic atherosclerosis or thrombus. May be indicated in clients with pulsatile abdominal mass, poor circulation of the legs, recent abdominal trauma, and suspected idiopathic aortitis.
Description.
Evaluation of the structure, size, and position of the abdominal aorta and branches (celiac trunk and renal, superior mesenteric, and common iliac arteries) by the creation of an oscilloscopic picture from the echoes of high-frequency sound waves passing over the anterior portion of the trunk (acoustic imaging). The time required for the ultrasonic beam to be reflected back to the transducer from differing densities of tissue is converted by a computer to an electrical impulse displayed on an oscilloscopic screen to create a three-dimensional picture of the abdominal aorta and branches. Ultrasonography allows measurement of the luminal diameter of the aorta. A narrowed lumen would indicate atherosclerosis or thrombus, whereas a wider-than-normal lumen with an irregular border may indicate aneurysm. Scattered internal echoes within the aneurysm may indicate an internal clot. A double lumen may indicate a tear in the wall of the abdominal aorta. Surgical grafts from aneurysm repair appear as bright echo reflections.
Professional Considerations
Consent form NOT required.
Preparation
1. This test should be performed before intestinal barium tests or else after the barium is cleared from the system (with allowance of several days for clearance).
2. An enema may be prescribed to be given before the ultrasonogram is taken.
3. The client should wear a gown.
4. Obtain ultrasonic gel or paste.
Procedure
1. Client is positioned supine on a procedure table.
2. The abdomen is covered with conductive gel.
3. A lubricated transducer is passed slowly along the abdomen at 1-cm intervals along the transverse and then longitudinal lines, covering the area between the xiphoid process and the symphysis pubis. If dissection is suspected, real-time techniques can be used more specifically to locate the site.
4. Photographs are taken of the oscilloscopic images.
5. Procedure takes less than 60 minutes.
Postprocedure Care
1. Cleanse skin of ultrasonic gel.
Client and Family Teaching
1. Eat a low-residue diet the day before the ultrasonogram is taken, fast from food and fluids after midnight before the test, and refrain from smoking.
2. Lie as still as possible during the procedure, which is painless and carries no risks.
3. Results are normally available within 24 hours.
Factors That Affect Results
1. Dehydration interferes with adequate contrast between organs and body fluids.
2. Intestinal barium or gas obscures results by preventing proper transmission and deflection of the high-frequency sound waves.
3. The more abdominal fat present, the greater is the attenuation (reduction in sound-wave amplitude and intensity), which interferes with the clarity of the picture.
4. Aorta may be displaced by scoliosis, a retroperitoneal mass, or the para-aortic lymph nodes; in some clients, these anomalies can mimic an aneurysm.
Other Data
1. There is some evidence that aneurysms smaller than 4 cm in diameter may be safely followed by ongoing monitoring and any aneurysm larger than 4 cm in diameter should be considered for surgery.
2. Ultrasound ranks below CAT scan (or CT scan) in its accuracy; however, it surpasses CT in screening.
Abdominal Plain Film
See Flat-Plate Radiography of Abdomen—Diagnostic .
Abdominal Ultrasound
See Abdominal Aorta Ultrasonography—Diagnostic ; Gallbladder and Biliary System Ultrasonography—Diagnostic ; Liver Ultrasonography—Diagnostic ; Obstetric Ultrasonography—Diagnostic ; Pancreas Ultrasonography—Diagnostic ; and Spleen Ultrasonography—Diagnostic .
Abeta
See Beta-Amyloid Protein—CSF .
ABG
See Blood Gases, Arterial—Blood .
ABI
See Ankle-Brachial Index—Diagnostic .
ABO Group and Rh Type— Blood
Norm.
Specific to each individual.
Usage.
Blood transfusion therapy, erythroblastosis fetalis, paternity determinations, pregnancy, and preoperatively.
Description.
The ABO blood group is the phenotype of a client's blood resulting from genetic inheritance. The four most common phenotypes are A, B, AB, and O, referring to the type of antigen present on the surface of red blood cells. Rh type refers to whether an Rh antigen is present (Rh positive) or absent (Rh negative) on the surface of a client's red blood cells. Routine testing usually involves only the Rh 0 (D) antigen. If an Rh-negative client receives Rh-positive blood, he or she will develop Rh antibodies, and future Rh-positive transfusions may cause a transfusion reaction. In pregnancy, antibodies from an Rh-negative mother may hemolyze fetal erythrocytes in a fetus that has inherited the Rh-positive antigen from the father (erythroblastosis fetalis, or hemolytic disease of the newborn). This test determines the specific ABO phenotype and Rh type by determining which A and B red blood cell antigens are present as well as whether the Rh 0 (D) antigen is present.
Professional Considerations
Consent form NOT required.
Preparation
1. Assess client for history of recent blood transfusion reaction, which can result in a positive antibody screen and require further testing. Write affirmative history on blood bank requisition.
2. Tube: Red topped, red/gray topped, or gold topped, 1 or 2 tubes.
Procedure
1. Ask the client to state full name and compare with the client's name band. Label the sample tube and laboratory requisition with the client's name, identification number, date, time, and initials and sign it. Some institutions require additional data.
2. Draw one or two 10-mL blood samples, depending on institutional requirements.
Postprocedure Care
1. Some institutions require application of a blood band to the client's wrist. The blood bank identification numbers should match the identification numbers on any blood bag used for transfusion for the client.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Hemolyzed specimen invalidates results.
2. Specimen drawn from extremity into which blood or dextran is infusing invalidates results.
3. Drugs causing a false-positive Rh test include levodopa, methyldopa, and methyldopate hydrochloride.
4. Abnormal plasma proteins, cold autoagglutinins, positive direct antiglobulin test, and in some cases, bacteremia may interfere with results.
Other Data
1. The test must be performed within 48 hours of specimen collection.
2. Amerindians are blood group O. Incompatible platelet products that are transfused can cause acute intravascular hemolysis.
3. ABO incompatibility is a significant prognostic risk factor in allogeneic bone marrow transplant for acute myelogenous leukemia or myelodysplastic syndrome.
4. See also Type-and-crossmatch, Blood .
Abscess
See Body Fluid—Anaerobic Culture .
ACA
See Antiphospholipid Antibodies—Serum .
Accu-Chek
See Glucose Monitoring Machines—Diagnostic .
ACE
See Angiotensin-Converting Enzyme—Blood .
Acetaminophen— Serum
Norm.
2 months to 10 years (received >60 mg of APAP/kg/day) = 0-23 mg/mL.
4 Hours After Last Dose SI Units
Therapeutic level 10-30 µg/mL 66-199 µmol/L
Toxic level >150 µg/mL >990 µmol/L
Panic level (hepatotoxicity) >200 µg/mL >1320 µmol/L View full size
APAP, N -acetyl- p -aminophenol.
Overdose Symptoms and Treatment
Symptoms.
Occur in four stages.
1. Stage I (ingestion to 24 hours): Gastrointestinal irritation, pallor, lethargy, diaphoresis, metabolic acidosis, and coma (cases of massive ingestion with serum concentration >800 µg/mL have been reported, but coma is usually attributed to a coingestant such as alcohol).
2. Stage II (24 to 48 hours): Increased serum hepatic enzymes, right upper quadrant abdominal pain, possible decreased renal function.
3. Stage III (72 to 96 hours): Increased AST, increased ALT, nausea, vomiting, jaundice, lethargy, confusion, coma, coagulation disorders, possible decreased renal function.
4. Stage IV (4 days to 2 weeks): Clinical symptoms subside; laboratory values return to baseline.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Establish and maintain adequate airway, respiratory, and circulatory function.
2. If client is obtunded or unconscious, appropriate doses of thiamine, dextrose, and naloxone must be considered.
3. Gastric decontamination: In one study, rapid complete bowel lavage with 4 g of polyethylene glycol electrolyte solution was shown to significantly reduce serum acetaminophen levels. In another study, use of activated charcoal prevented acetaminophen absorption when given within 60 minutes of acetaminophen ingestion. An emetic may be used to induce emesis for recent ingestion, but it must be used with extreme caution. Ondansetron can be used to manage vomiting if acetaminophen ingestion occurred within the previous 8 hours.
4. Oral administration of N -acetylcysteine (Mucomyst by Mead Johnson) for suspected toxic doses (>7.5 g). Mucomyst is most likely to be effective when given within 16 hours after acetaminophen ingestion.
5. Laboratory monitoring: Urine toxicology screen, hepatic profile daily for 3-4 days, BUN, Cr, serum electrolytes, serum acetaminophen concentration level 4 hours after ingestion.
6. Coingestion of other substances that delay gastric emptying is an indication for serial measurement to detect late-rising acetaminophen levels.
7. Chronic alcohol intake enhances acetaminophen hepatotoxicity.
8. Hemodialysis WILL but peritoneal dialysis will NOT remove acetaminophen.
Usage.
Drug abuse, hepatitis, monitoring for toxicity during acetaminophen therapy, overdose, poisoning, and suicide.
Description.
Acetaminophen (also known as paracetamol) is a p -aminophenol derivative that has antipyretic (direct action on hypothalamus) and moderate analgesic actions. It is absorbed by the gastrointestinal tract and metabolized by liver microsomes. Half-life is 1 to 4 hours with peak blood levels reached in 30 minutes to 1 hour. Used for headache, fever, and relief of pain in clients who cannot tolerate aspirin or those with peptic ulcers or bleeding disorders. It is the drug of choice (antipyretic/analgesic) in children 13 years of age and younger because of the possible development of Reye's syndrome associated with aspirin. In adults, ingestion of more than 4 g/day can be hepatotoxic.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, gold topped, or lavender topped.
2. Do NOT draw during hemodialysis.
3. Document times of ingestion and sample collection on lab requisition.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 24 hours.
2. If overdose is suspected, prepare client and family for necessary supportive treatment described above.
3. If activated charcoal was given for elevated levels, client should drink 4 to 6 glasses of water each day for 2 days to prevent constipation. Activated charcoal will also cause stools to be black for a few days.
Factors That Affect Results
1. Cardiovascular, hepatic, gastrointestinal, or renal dysfunction can alter drug absorption and elimination.
2. Toxic levels of acetaminophen positively interfere with glucose-monitoring machine results.
3. Draw two samples, 4 hours apart, to determine the half-life of acetaminophen.
Other Data
1. Acetaminophen is present in many medicines: Anacin 3, Datril, Liquiprin, Panadol, Panex, paracetamol, Phenaphen, Tempra, and Tylenol.
2. Acetaminophen used with aspirin and caffeine alleviates migraine headache pain.
3. Premedication with acetaminophen does not significantly lower the incidence of nonhemolytic transfusion reactions.
4. Acetaminophen poisoning has been found in nearly 50% of all acute liver failure in the United States.
5. Prothrombin time prolongation may be noted in clients with hepatic failure and paracetamol poisoning.
Acetone
See Acetone—Urine ; Ketone Bodies—Blood or Toxicology; Volatiles Group by GLC—Blood or Urine .
Acetone— Urine
Norm.
Keto-Diastix or Multistix: Negative. Quantitative 0.3-2.0 mg/dL.
Usage.
Differentiation of diabetic coma and insulin shock, evaluation of glucose control in diabetics, preadmission screening, pregnancy, screening for ketoacidosis, and monitoring for occupational exposure to isopropyl alcohol. Increased in ethanol hangover and in ingestion of denatured alcohol.
Description.
Acetone is a by-product of fat and fatty acid metabolism that provides a source of cellular energy for cells when glucose stores are exhausted or when glucose is prevented from entering cells because of lack of insulin. Acetone entering the bloodstream is almost completely metabolized in the liver. When acetone is formed at a faster-than-normal rate or is present in the bloodstream in higher-than-normal levels, it is excreted in the urine.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a clean urine container and acetone testing strips or tablets.
2. Client should empty the bladder 30 minutes before specimen collection and then drink a glass of water.
3. For specimens obtained from an indwelling urinary catheter, also obtain a catheter clamp, a sterile 10-mL syringe and needle, and an alcohol wipe.
Procedure
1. Obtain a 20-mL double-voided urine specimen in a clean container.
2. Specimens from catheter: Clamp the catheter tubing for 15 minutes to allow urine to accumulate above the sample port. Cleanse the sample port with an alcohol wipe and allow to dry. Aspirate 20 mL of urine from the sample port, using a sterile syringe and needle. Collect only fresh urine that has accumulated above the sample port. Unclamp the catheter tubing.
3. Dip the Keto-Diastix, Multistix, or other acetone testing material in fresh urine and hold the strip horizontally for 15 seconds.
4. Compare the color of the ketone patch on the strip with the color chart on the container of acetone testing strips.
5. Alternative method using Acetest tablets: Place a drop of urine on an Acetest tablet and wait 30 seconds. Compare the color with the Acetest color chart.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are immediately available.
Factors That Affect Results
1. Fasting or dieting may cause acetone to appear in the urine.
2. Use of acetone tablets that are darkened or expired invalidates results.
3. Drugs that may cause false-positive results include captopril, levodopa, paraldehyde, and phenazopyridine hydrochloride.
4. Gender and ingestion of alcohol may affect the basal levels of urinary acetone.
Other Data
1. Refrigerate the specimen if the test cannot be performed within 1 hour of collection.
2. In one study, ratings on scales of well-being and acute symptoms correlated significantly with the concentration of acetone in urine after acute airborne acetone exposure.
3. See also Ketone, semiquantitative—Urine .
Acetylcholine Receptor Antibody— Serum
Norm.
≤ 0.03 nmol/L.
Usage.
Diagnosis and clinical monitoring of myasthenia gravis, Lambert-Eaton myasthenic syndrome, small cell lung carcinoma.
Description.
In clients with myasthenia gravis, this antibody interferes with the binding of acetylcholine to receptor sites on the muscle membrane, thus preventing muscle contraction. Assays for acetylcholine receptor (AChR) antibodies are positive in 85%-90% of clients with acute myasthenia gravis and are replacing the Tensilon test as a diagnostic aid for this condition. However, this assay is less sensitive for Lambert-Eaton myasthenic syndrome diagnosis.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List on the laboratory requisition any recent immunosuppressive drug therapy the client received.
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results may not be available for several days.
Factors That Affect Results
1. False-positive results may be caused by D-penicillamine.
2. Decrease in titer may be caused by intravenous immunoglobulin (IVIg) therapy.
3. Clients with orthostatic hypotension may have a seropositive AChR antibody.
Other Data
1. Undetectable titer occurs in 33.4% of clients who have only ocular myasthenia gravis.
2. See also Tensilon test—Diagnostic .
Acetylsalicylic Acid
See Salicylate—Blood .
ACG— Diagnostic
See Apexcardiography—Diagnostic .
Acid-Fast Bacteria— Culture and Stain
Norm.
Negative.
Usage.
Acquired immune deficiency syndrome (AIDS); suspected Helicobacter pylori , intestinal parasites, leprosy, mycobacteriosis, or tuberculosis; and differentiation of tuberculosis from carcinoma and bronchiectasis.
Description.
Mycobacterium tuberculosis is a rod-shaped bacterium that resists decolorizing chemicals after staining, a property termed “acid-fastness .” M. tuberculosis is transmitted most commonly by the airborne route to the lungs, where it survives well, causes areas of granulomatous inflammation, and, if not dormant, causes cough, fever, and hemoptysis. The acid-fast bacterium Mycobacterium avium-intracellulare is a common cause of infection in clients with AIDS. Culture of sputum is necessary to confirm the diagnosis of tuberculosis and for sensitivity studies for drug therapy. The sensitivity of sputum smears for tuberculosis, however, is only 50%. The CDC recommends that every client with suspected tuberculosis also have nucleic acid amplification testing performed on at least one respiratory specimen. Nucleic acid amplification testing provides earlier confirmation (24-48 hours) of tuberculosis than does culture.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain three small, sterile containers.
2. See Client and Family Teaching .
Procedure
1. Aerosolized therapy before sputum collection may stimulate sputum production and produce a better specimen.
2. When tuberculosis is suspected, collect three daily, early-morning sputum, deep-cough specimens in a sterile container.
3. When leprosy is suspected, obtain smear from nasal scrapings or biopsy from lesions and place in sterile container.
Postprocedure Care
1. Provide mouth care.
Client and Family Teaching
1. Perform oral hygiene before giving specimens to reduce chances of contamination.
2. Deep coughs are necessary to produce sputum, rather than saliva. To produce the proper specimen, take several breaths in, without fully exhaling each, and then expel sputum with a “cascade cough.”
Factors That Affect Results
1. Antituberculous drug therapy may cause negative results because of inhibition of growth of M. tuberculosis .
2. A high–carbon dioxide atmosphere for growth may increase the number of positive cultures.
3. Culture medium containing glycerin accelerates growth.
Other Data
1. Culture results may take 3-8 weeks.
2. The most prevalent intestinal parasites in cancer clients diagnosed by acid-fast stain are Entamoeba histolytica/Entamoeba dispar (8.5%), Giardia lamblia (3.1%), Strongyloides stercoralis (0.6%), and Cryptosporidium parvum (0.3%).
Acid-Fast Stain, Nocardia Species— Culture
Norm.
Negative.
Usage.
Aids in diagnosis of Behçet's disease, mycetoma, Nocardia brasiliensis , and nocardiosis of the respiratory tract found in persons with systemic lupus erythematosus and nocardial thyroiditis.
Description.
Nocardia is an aerobic, gram-positive, filamentous branching bacterium that segments into reproductive bacillary fragments. It is weakly acid fast; found outdoors in decayed matter, soil, grass, and straw; and enters the body primarily through inhalation of contaminated dust. The type species, Nocardia asteroides , and N. brasiliensis, N. farcinica, N. otitidis-caviarum, N. nova, and N. transvalensis cause a variety of diseases in both normal and immunocompromised humans and animals. The N. asteroides species causes primary skin lesions, visceral infections (most commonly abscesses of the lungs, brain, and subcutaneous tissue), and sometimes disseminated infections in humans.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a sterile scalpel or spatula, or a sterile needle and syringe, and both anaerobic and aerobic culture media.
Procedure
1. Obtain a scraping from a skin lesion or an aspirate of an abscess using sterile technique.
2. Inoculate both aerobic and anaerobic culture media with the specimen.
3. Aerobic culture media of beef infusion broth or thioglycolate broth may be used.
4. Initial incubation at temperatures from 38 to 45 degrees C should be used.
5. Examine cultures for growth beginning at 48 hours and recheck daily for 2 weeks.
Postprocedure Care
1. Apply dry sterile dressing to site.
Client and Family Teaching
1. Avoid application of creams or lotions to sample site and allow site to remain open to air for healing.
2. At least 2-3 days are required for growth and results.
Factors That Affect Results
1. Nocardia growth may be mistaken for nontuberculous Mycobacterium when a Mycobacterium culture medium is used.
Other Data
1. Common specimens include pus, tissue, body fluid, and sputum.
2. Final reports may take 10 days.
Acid Hemolysin Test— Blood
See Ham's Test—Blood .
Acidified Serum Test— Blood
See Ham's Test—Blood .
Acid Phosphatase— Serum
Norm.
Method SI Units
Bodansky 0.5-2 U/L 2.7-10.7 IU/L
King-Armstrong 0.1-5 U/L 0.2-8.8 IU/L
Bessey-Lowery-Brock 0.1-0.8 U/L 1.7-13.4 IU/L
Gutman 0.1-2 U/L View full size
Increased.
Bone fracture, cancer with bone metastasis, Gaucher disease, hairy cell leukemia (leukemic reticuloendotheliosis), hepatitis (viral), hyperparathyroidism, hypophosphatemia, idiopathic thrombocytopenic purpura (with bone marrow megakaryocytes), jaundice (obstructive), Laënnec's cirrhosis, leukemia (myelogenous), multiple myeloma, osteogenesis imperfecta, Paget's disease (advanced), partial translocation trisomy 21, prostate cancer, prostatic infarction, prostatic surgery or trauma, renal impairment (acute), sickle cell crisis, thrombocythemia, thrombocytosis, thromboembolism, and thrombophlebitis. Drugs include anabolic steroids.
Decreased.
No clinical significance. Drugs include fluorides.
Description.
Acid phosphatase is one of a group of enzymes located primarily in the prostate gland and prostatic secretions. Smaller amounts are found in the bone marrow, spleen, liver, kidneys, and blood components such as erythrocytes and platelets. Isoenzymes of acid phosphatase include prostatic isoenzyme and erythrocytic isoenzyme. Used in diagnosis of and monitoring for treatment response of prostate cancer.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Collect a 4-mL blood sample.
Postprocedure Care
1. Send the specimen to the laboratory immediately.
2. Separate the serum, add 0.01 mL of 20% acetic acid per milliliter of serum, and refrigerate if the test is not performed immediately.
Client and Family Teaching
1. Results may not be available for several days.
Factors That Affect Results
1. Hemolysis or specimens received more than 15 minutes after collection invalidate results.
2. False-negative results may be attributable to use of a collecting tube containing fluorides, oxalates, or phosphates.
3. Drugs that cause false-positive results include clofibrate.
4. Elevated levels may be caused by rectal examination, prostatic massage, or urinary catheterization within 2 days before the test.
Other Data
1. This test is more helpful for diagnosis in advanced prostate cancer than in early prostate cancer.
2. Use of prostate-specific acid phosphatase as a tumor marker for prostate cancer is being replaced by Prostate-specific antigen—Serum.
3. See also Prostatic acid phosphatase—Blood .
Acid Phosphatase, Tartrate-Resistant— Blood
See Tartrate-Resistant Acid Phosphatase Stain—Specimen .
Acid Phosphatase— Vaginal Swab
Norm.
Method: Dilution with a substrate of thymolphthalein monophosphate.
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Inconclusive7-50 Highly suggestive of coitus within past 36 hours
≥50 Confirmation of recent coitus View full size
Usage.
Rape trauma workup.
Description.
Acid phosphatase is one of a group of enzymes located primarily in the prostate gland and prostatic secretions, with smaller amounts found elsewhere in the body. Normal vaginal secretions contain only low levels of acid phosphatase. Because acid phosphatase is found in such high concentrations in semen, its isolation in high levels from vaginal fluid in cases of suspected rape is strong evidence that coitus occurred recently.
Professional Considerations
Consent form NOT required unless specimen may be used as legal evidence.
Preparation
1. Obtain speculum, cotton wool swab supplied in a sexual offense kit, and sterile container.
Procedure
1. If the specimen may be used as legal evidence, have the specimen collection witnessed.
2. Position the client in the dorsal lithotomy position and drape for privacy and comfort.
3. Gently scrape the walls of the vagina with a plain cotton wool swab until it is saturated.
4. Place the swab in a sterile container.
Postprocedure Care
1. Write the client's name, the date, the exact time of collection, and the specimen source on the laboratory requisition. Sign and have the witness sign the laboratory requisition.
2. Transport the specimen to the laboratory immediately in a sealed plastic bag marked as legal evidence. All clients handling the specimen should sign and mark the time of specimen receipt on the laboratory requisition.
Client and Family Teaching
1. Provide repeated and thorough explanation of the purpose and process of specimen collection.
2. Follow-up: Survivors of sexual assault should be referred to appropriate crisis counseling agencies as well as gynecologic follow-up. Facilitate referral if desired by client.
3. Referral for HIV testing should be reviewed and offered to all sexual assault victims.
4. Preventive treatment for Chlamydia , gonorrhea, and syphilis should be provided to all survivors of sexual assault.
5. The option of postcoital contraceptive should be reviewed with all survivors of sexual assault.
Factors That Affect Results
1. Vaginal swabs for acid phosphatase should be collected as soon as possible after the assault. Swabs have the highest chance of being positive when collected within 5 hours of the assault and are least likely to be positive after 12 hours. By 48 hours, normal vaginal levels are usually found.
2. Negative results may be obtained if the assailant was sexually dysfunctional or has had a vasectomy or if the client bathed, douched, or defecated after the assault.
3. This test cannot identify the perpetrator.
4. Contamination of the vagina or the specimen with substances other than semen or normal vaginal substances may cause false-positive results.
Other Data
1. Negative results caused by a long delay between the occurrence of the assault and collection of the vaginal specimen are sometimes used by defense attorneys as evidence that a rape did not occur.
2. Although swabs may also be taken of other body orifices for evidence of acid phosphatase, they rarely yield positive results when taken more than 5 hours after the sexual assault occurred.
3. A spot test, intended for field use outside of the lab, is currently being tested. A test swab is covered with the moistened specimen, and characteristic color changes in the swab indicate positive or negative presence of acid phosphatase. Vaginal washings should be evaluated within 24 hours of deposition. Results are independent of sperm count.
4. See also Blood group antigen of semen—Vaginal swab ; Precipitin test against human sperm and blood—Vaginal swab .
Acoustic Immittance Tests— Diagnostic
Norm.
Normal acoustic immittance.
Tympanogram.
The tympanogram recording shows a symmetric, shallow upslope and downslope free of notches or peaks with middle ear pressure of −100 to +100 dPa.
Pure-Tone Reflex Threshold
Transbrainstem 70-100 dB HL
Ipsilateral 3-12 dB HL
Reflex decay < baseline/10 seconds View full size
Usage.
Assessment of middle ear and tympanic membrane functioning; identification of location of middle ear lesions; and differential diagnosis of brainstem lesions and hearing loss; evaluation of tinnitus or vertigo; and evaluation of Bell's palsy.
Description.
The acoustic immittance tests measure middle ear functioning and locates abnormalities by tympanometry and measurement of acoustic reflexes and static acoustic impedance. Tympanometry assesses stiffness of the middle ear by measuring admittance (that is, how much impedance exists to the flow of sound into the ear). Lower than normal admittance can be caused by cerumen, the presence of fluid in the middle ear, or a perforated tympanic membrane. Higher than normal admittance results when ear scarring is present. Measurement of acoustic reflexes shows how well the stapedius muscle responds to the delivery of sound against it. Poor or no acoustic reflexes can indicate hearing loss, neurologic or stapedius muscle damage or lesions, otosclerosis, or absence of the stapes.
Professional Considerations
Consent form NOT required.
Risks
Infection.
Contraindications
May be contraindicated in clients with accidental head injuries or suspected labyrinthine fistula or in those who have recently undergone ear surgery.
Preparation
1. Obtain admittance meter; recorder; probe with tips, cuffs, and silicone putty; otoscope; and audiometer.
2. See Client and Family Teaching .
Procedure
1. Cleanse the bores of the ear probe with wire. Calibrate the admittance meter. Inspect the ear canal, and remove any impacted cerumen.
2. Lift the auricle up and out, and insert the admittance meter's cuffed probe into the external auditory canal until a pressure of −200 dPa is achieved, indicating an adequate seal.
3. Admittance measurement: Admittance recordings are made in response to air-pressure changes made by the meter.
4. Acoustic reflex measurement: Measure acoustic reflexes when a 500- to 4000-Hz tone is sent into either ear. Perform ipsilateral measurement in the stimulated ear. You may perform contralateral (transbrainstem) measurement by sending the tone into the opposite ear.
5. Reflex-threshold measurement: Measure the reflex threshold by sending progressively louder tones into the ear in 10-dB increments until a reflex occurs and then decreasing the decibels in smaller steps until the lowest level that elicits a reflex is identified.
6. Reflex-decay measurement: Measure the reflex decay by sending a 10-second tone equal to the reflex threshold plus 10 dB into the contralateral ear and comparing the degree of initial, 5-second, and 10-second reflexes.
Postprocedure Care
1. Cleanse the ear probe.
Client and Family Teaching
1. Avoid moving, talking, or swallowing during the test. The test involves transmitting loud tones into the ear, which may be uncomfortable but will not damage the ear.
Factors That Affect Results
1. The most accurate results are obtained when the air seal remains continuous. Silicone putty may be used around the circumference of the canal to help maintain the seal.
2. Cerumen or silicone putty clogging the probe may cause the tympanogram to show as a flat waveform.
Other Data
1. Incidence of hearing loss is 46% for persons more than 66 years of age, is greater in males than in females, and increases with age.
Acquired Immune Deficiency Syndrome (AIDS) Evaluation Battery— Diagnostic
Norm.
Negative AIDS battery, nonreactive.
Antigen Detection by Serology.
Negative for HIV antigens.
Antibody Detection.
Negative for HIV antibodies.
Lymphocyte Subset Enumeration
Total 1500-4000/mL
B cells 65-475/mL
OKT-3 cells 875-1900/mL
OKT-4 cells (CD4) 450-1400/mL
OKT-8 cells 190-725/mL
OKT-4:OKT-8 ratio 1-3.5
Beta 2 -microglobulin <2 full="" mg="" ml="" nbsp="" nmol="" p="" si="" size="" units="" view="">Usage.
Used often in combination with cultures and for confirmation of opportunistic infection to help diagnose acquired immune deficiency syndrome (AIDS). Included in well-woman screening recommendations from the American College of Obstetricians and Gynecologists for clients with any of the following risk factors: more than one sexual partner since their most recent HIV test or a sexual partner with more than one sexual partner since their most recent HIV test, diagnosed with a sexually transmitted disease in the past year, drug use by injection, invasive cervical cancer, and women seeking preconception evaluation.
Description.
AIDS is caused by human immunodeficiency virus (HIV), a cytoplasmic retrovirus of the human T-cell leukemia and lymphoma virus family that reproduces and infects, even when antibodies against the virus are present. There are several strains. All attack a subgroup of T- lymphocytes known as “helper” T cells, which are important in cell-mediated immunity. AIDS causes immunosuppression and susceptibility to infection with opportunistic organisms such as Pneumocystis carinii, Candida albicans, Cryptococcus neoformans, Mycobacterium, Toxoplasma gondii, Cryptosporidium , and herpes simplex. The predominant modes of transmission of HIV are believed to be (1) direct contact between the blood of an uninfected person and the blood of an infected person and (2) sexual and body fluid transmission. The incubation period may be as short as 6 days and as long as several years.
HIV is now the leading cause of death in men 25-40 years of age, the sixth leading cause of death worldwide in adolescent males 15-24 years, and the fourth leading cause of death in women 25-44 years. It is estimated that 42 million people worldwide, including 980,000 North Americans, are HIV infected. In 2002 3.1 million people died of HIV/AIDS and AIDS-related diseases.
A person may be infected with the human immunodeficiency virus for several years without becoming symptomatic when the virus enters a non-replicating latent period. When the virus begins actively replicating, the person may develop AIDS. At 2-6 weeks after infection, clients may develop a viral-like illness consisting of fever, sweats, fatigue, malaise, lymphadenopathy, sore throat, and sometimes splenomegaly. Clients may remain asymptomatic for months to years, depending on the progression of the disease.
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The AIDS evaluation battery results are not usually performed unless a rapid screening test is preliminarily positive (see OraQuick rapid HIV tests—Specimen ). The tests in this battery are often considered with other diagnostic tests for opportunistic infection such as body fluid culture and cytology, central nervous system tomography, bronchoscopy, and biopsy to complete the clinical picture description before diagnosis is made. The AIDS evaluation battery comprises the following tests: blood and body fluid cultures, antigen detection by serology, antibody detection, confirmatory antibody detection methods, and tests for immunologic status evaluation and beta 2 -microglobulin. No test that by itself confirms HIV infection has yet been developed.
Blood and body fluid cultures have been found to show positive results in some persons soon after infection with HIV. Although difficult to do, isolation of HIV has been accomplished in concentrated peripheral blood lymphocytes and body fluids. However, a negative result does not rule out infection (see Blood culture—Blood ; Body fluid, Routine—Culture ).
Antigen detection by serology methods may be positive for the viral antigen (frequently p24 core protein, HIV core antigen) from 1-2 weeks up to about 1 month after infection with the virus. The antigen is detectable during acute (initial) infection, undetectable as the virus becomes latent, and again detectable as the infection progresses. The enzyme-linked immunosorbent assay (ELISA) is used for screening for HIV. Detection of HIV antibody by ELISA must be confirmed by Western blot. Alternative diagnosis may be made by viral culture, by antigen detection, or by HIV DNA or RNA polymerase chain reaction (PCR). Quantitative virology using quantitative RNA PCR or branched-chain DNA (bDNA) has become a popular method to access viral load in staging clients or for therapeutic monitoring. Maternal antibodies may be present in infants until 18 months of age; therefore CD4 counts, viral culture, or PCR followed by antibody detection after 18 months must be performed to diagnose HIV in infants.
Studies indicate that the frequency of false-positive tests in a low-prevalence population with both the ELISA and Western blot is about 0.0007%, and the frequency of false-negative results in a high-prevalence population is about 0.3%. The usual cause of false-negative tests is testing in the time between transmission and seroconversion, a period that rarely lasts longer than 3 months. When the results are positive, it is recommended that repeat testing be done for those with no likely risk factors, and those who report positive results from an anonymous test site. Periodic tests are suggested for clients with negative results who continue to practice high-risk behaviors.
Confirmatory antibody detection methods include the Western blot, immunofluorescence, radioimmunoprecipitation, and ELISA tests that detect antibodies to genetically engineered HIV proteins. The Western blot and immunofluorescence methods have similar sensitivities. Immunofluorescence results are obtained more quickly but are less reliable than those of the Western blot. Radioimmunofluorescence is more sensitive than the Western blot but is not widely used because of the technical difficulty of the procedure. Newer ELISA tests are able to pinpoint the specific HIV antibody present in serum when one incubates the serum first with specific HIV proteins and then a tagged, anti-immunoglobulin enzyme and measures the amount of substrate hydrolyzed by the antigen-antibody reaction.
Quantitative testing for HIV p24 antigen may provide a surrogate marker for disease progression: however, this antigen usually disappears from the blood during the asymptomatic phase. The PCR for the detection of HIV DNA or RNA has been extensively used in the research setting and proven extremely valuable.
A few alternative detection methods are actively being studied. Two home test kits for HIV detection (Direct Access Diagnostics and ChemTrak) are under review by the FDA. There are currently two FDA-licensed rapid tests: SUDS (Murex) and Recombigen latex agglutination assay (Cambridge Biotech). These tests are attractive for use in areas such as emergency departments, autopsy areas, and STD clinics.
Tests for immunologic status evaluation include lymphocyte subset enumeration, T-lymphocyte and B-lymphocyte subset assays, and skin tests with known antigens for persons with infections such as Candida or mumps; these often demonstrate normal results until the later stages of infection. As T-lymphocyte helper cells (OKT-4 cells) become infected by the human immunodeficiency virus, their numbers decrease. Levels of suppressor T cells (OKT-8 cells) may remain normal or increase as virus activity progresses. Lymphocyte counts decrease as immune function decreases. False-negative results from known antigen skin tests indicate that the client's immune function is compromised.
Beta 2 -microglobulin is an amino acid peptide component of lymphocyte HLA complexes that increases in the serum in inflammatory conditions and when lymphocyte turnover increases, as when T-lymphocyte helper (OKT-4) cells are attacked by HIV. Rising levels may also be caused by conditions other than HIV. Although beta 2 -microglobulin levels usually rise with HIV infection, the levels do not always correlate with the stages of the infection (see Beta 2 -microglobulin—Blood and 24-hour urine ).
CD4+ T-lymphocyte test results alone should not be used as a surrogate marker for HIV or AIDS. A low CD4+ T-lymphocyte count without a positive HIV test result will not be reportable, since other conditions may be the cause. Health care providers must ensure that persons who have a CD4+ T-lymphocyte count of <200 are="" before="" disease.="" for="" hiv-infected="" hiv="" initiating="" p="" treatment="">
Professional Considerations
Consent form IS required because of area-specific legal regulations. Testing should be voluntary with appropriate counseling before and after informed consent.
Preparation
1. Clarify the type of tube needed for lymphocyte subset enumeration if the Becton Dickinson Immunocytology Systems method is not used.
2. Tube: Red topped, red/gray topped, gold topped, or lavender topped.
Procedure
1. Antigen detection by serology, antibody detection, and confirmatory antibody detection method: Draw a 5-mL venous blood sample.
2. Lymphocyte subset enumeration (Becton Dickinson Immunocytology Systems method): Completely fill two lavender topped tubes with venous blood. Label one tube for complete blood count and the other tube for lymphocyte subset enumeration.
3. Beta 2 -microglobulin: Draw a 10-mL venous blood sample in a lavender topped tube.
Postprocedure Care
1. Either leave reusable equipment in the client's room or dispose of the equipment in the room.
Client and Family Teaching
1. Explain the purpose of the test, the procedure for collection, and the results to the client.
2. Two days are required for the Western blot.
3. Assess client understanding of safe sex practices and provide counseling as needed.
4. CDC National AIDS hotline: 1-800-342-AIDS.
Factors That Affect Results
1. Antibody results may be negative up to 35 months after infection because of viral latency.
2. False-positive ELISA results may be caused by HLA antibody reaction with specific proteins in certain test kits. False-negative ELISA results may occur in a small proportion of clients with HIV-1 infection and in some children infected with HIV in utero.
3. Falsely depressed lymphocyte counts may be caused by steroids and general anesthetics.
4. Beta 2 -microglobulin results are invalidated if the person has undergone a scan involving the administration of radioactive dyes within 1 week before the test.
Other Data
1. Legal restrictions exist and vary regarding HIV testing and reporting of results.
2. Demonstration of homogeneous B or T-lymphocytes is helpful in prognosis and therapeutic planning of malignant lymphoproliferative disorders.
3. In a recent study at the National Institute of Allergy and Infectious Diseases, in a small number of HIV-infected clients, infusions of an immune system protein significantly increased levels of the infection-fighting white blood cells normally destroyed during HIV infection.
4. Begin antiretroviral therapy before CD4 cells drop below 200/µL.
5. Progression of cytomegalovirus retinitis occurs in 17% with low CD4 cell count.
6. The Genie assay is faster, less costly, and yields fewer indeterminate results in detecting HIV-1 antibodies than the Western blot method.
7. Independent predictors to progression include CD4 <50 3="" and="" carinii="" cells="" hemoglobin="" high="" levels="" load.="" low="" mm="" p="" pneumocystis="" pneumonia="" prophylaxis="" virus="">8. Total viral load can sometimes be assessed to help monitor the impact of treatment.
9. HIV testing should be performed at baseline, 4, 12, and 24 weeks.
10. See also T- and B-lymphocyte subset assay—Blood ; Beta 2 -microglobulin—Blood and 24-hour urine ; Oral mucosal transudate—Specimen ; and OraQuick rapid HIV test—Specimen .
ACTH Stimulation Test— Diagnostic
Norm.
17-Hydroxycorticosteroid (17-OHCS) levels increase by two to four times between the first and second 24-hour urine collection.
Usage.
Definitive diagnosis of Addison's disease and adrenal adenoma.
Description.
Adrenocorticotropic hormone (ACTH) is secreted by the pituitary gland and acts on the adrenal cortex to cause release of adrenal hormones. This test measures blood cortisol and urinary 17-OHCS levels before and after an infusion of ACTH. It is diagnostic of Addison's disease in a client with hypocortisolism when an infusion of ACTH fails to cause an increase in cortisol or 17-OHCS, urinary metabolites of plasma cortisol. A small response occurs in those with high mortality in the ICU and in older clients.
Professional Considerations
Consent form NOT required.
Preparation
1. To prevent hypersensitivity reactions when using biologic rather than synthetic ACTH, give 0.5 mg of dexamethasone orally before the test.
2. Obtain a 3-L container with 10 mL of concentrated hydrochloric acid (HCl) preservative.
3. Write starting time of collection on the laboratory requisition.
4. The test can be performed at any time of the day.
Procedure
1. Discard the first morning-urine specimen.
2. Save all urine voided for 24 hours in a refrigerated, clean, 3-L container to which 10 mL of concentrated HCl has been added. Document the quantity of urine output during the collection period. Include urine voided at the end of the 24-hour period.
3. Begin a second 24-hour urine collection.
4. During the second collection, infuse 24 units of ACTH in 500 mL of normal saline intravenously over 8 hours.
Postprocedure Care
1. Record the total 24-hour output on the laboratory requisition and send the entire specimen to the laboratory.
Client and Family Teaching
1. Save all urine voided in the 24-hour period, and urinate before defecating to avoid loss of urine. If any urine is accidentally discarded, discard the entire specimen and restart the collection the next day.
Factors That Affect Results
1. Maintenance steroids that must be given during the testing period should be in the form of small doses of dexamethasone to avoid false elevation of 17-OHCS in the urine.
Other Data
1. The test should be repeated in 24 hours if pituitary deficiency is suspected. Pituitary insufficiency would be evident by a gradual but small response to the ACTH stimulation test during the second test.
2. The ACTH stimulation test is useful for identifying adrenal insufficiency; however, it is not sensitive or specific for clients suspected of having secondary adrenal insufficiency or those with recent pituitary injury.
Actinomyces— Culture
Norm.
Negative.
Positive.
Abscess, actinomycosis, pelvic inflammatory disease, and root canal infection.
Description.
A slow-growing, gram-positive, non–acid-fast, bacillus that is anaerobic to microaerophilic and appears in variable lengths and shapes on a Gram stain. Actinomyces israelii is a part of the normal oral flora in many people. Possibly because of mouth trauma or infection, it sometimes becomes invasive, forms draining sinus tracts, and becomes a chronic, suppurative disease called “actinomycosis” that spreads by direct extension. The characteristic lesion is a hard, red, nontender nodule that eventually begins draining. The Actinomyces organisms are also found in the vaginal smears of a small percentage of women in whom intrauterine devices have been inserted.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a sterile cotton swab and culture media.
Procedure
1. Swab the drainage (pus from lesion, sinus tract, or fistula; or sputum; or tissue biopsy material).
2. Inoculate the drainage into thioglycolate medium and streak it onto brain-heart infusion agar plates.
3. Incubate anaerobically for 2 weeks or more.
Postprocedure Care
1. Apply a dry sterile dressing as needed.
2. Send the specimen to the laboratory immediately.
Client and Family Teaching
1. Results will not be available for at least 14 days.
2. Treatment for actinomycosis usually includes drainage of lesions and penicillin or tetracycline drug therapy.
Factors That Affect Results
1. Do NOT refrigerate or store the specimen.
Other Data
1. Some tissue damage from actinomycosis is irreversible.
Activated Coagulation Time (ACT), Automated— Blood
Norm.
Varies, depending on the type of system in use and the type of test reagent or activator. There are currently two commercially available systems for analyzing ACT by automation: ACT II by Medtronic Hemotec Inc. and Hemochron by International Technidyne Corporation.
Hemochron System
Tube Range in Seconds ACT II
TCA510 and FTCA510 105-167 Multiple methods are available for measuring ACT values; thus values should be evaluated according to reference levels of the individual machine and test tube used. The ACT II machine has an overall range of 0-999.
K-ACT and FTK-ACT 91-151
P214/215 110-182
S412 186-306 View full size
Usage.
Commonly used for heparin anticoagulation monitoring during bypass surgery, percutaneous transluminal coronary angioplasty (PTCA), interventional radiology, neonatal extracorporeal membrane oxygenation (ECMO), hemofiltration, hemodialysis, and critical and telemetry care.
Increased.
Afibrinogenemia, circulating anticoagulants, dysproteinemia, factor deficiency (V, VIII, IX, X, XI, or XII), fibrinolysis, hemophilia, hemorrhagic disease of the newborn, hypofibrinogenemia, hypoprothrombinemia, leukemia, and liver disease. Drugs include antithrombin III, aprotinin, heparin calcium, heparin sodium (including blood obtained from an introducer with a heparin-coated pulmonary artery catheter), and warfarin.
Description.
Measures the ability of blood to clot. Fresh whole blood is added to a test tube containing an activator (diatomaceous earth, glass particles, or kaolin) and timed for the formation of a clot. The ACT is more sensitive to the effects of factor VIII deficiency and heparin than is whole-blood clotting time. The ACT test has become a mainstay in monitoring heparin anticoagulation during invasive procedures and is the preferred method for monitoring high-level anticoagulation. The ACT is quick, reliable, and easy and can be performed at the bedside. Disadvantages of the ACT are operator variability and differences between the two commercially available systems.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a tube with a designated activator for the specific ACT test. May be drawn from indwelling venous blood line, extracorporeal blood line port, direct venipuncture, or vacuum draw. Do not obtain blood from a heparinized access line, an indwelling heparinized lock, or a hemodialysis line.
2. Obtain two 5-mL syringes.
Procedure (if using the ACT II system, see instructions below before obtaining client sample):
1. Indwelling venous line sampling : With the first syringe, withdraw and discard 5 mL of blood. Attach the second syringe and withdraw a 3-mL blood sample.
2. Venipuncture sampling : With the first syringe, withdraw and discard 2 mL of blood. Attach the second syringe and withdraw a 3-mL sample.
Hemochron System
1. Dispense exactly 2 mL of blood into the test tube (N ote : tubes P214/P215 require only 0.4 mL of blood). At the same time, depress the start-button timer on the machine. Close the tube and agitate it briskly 10 times.
2. Insert the test tube into the Hemochron machine port and rotate clockwise until the green indicator light is visible. Await the result, which will be displayed as the number of seconds required to obtain coagulation on the Hemochron screen.
Act II System
1. Prewarm the cartridge in the ACT heat block for 3 minutes.
2. Gently tap or shake the cartridge to resuspend the activator.
3. Inject the client sample into channel 2 and then channel 1 of the cartridge, filling to between the lines (<1 ml="" p="">4. Place the cartridge in the instrument and pull the actuator cover forward. The instrument will sound an audible alert when the end point is reached. (N ote : The instrument has two readout displays. The channel 1 result is of ACT without heparin; the channel 2 result is of ACT with the influence of heparin.)
Postprocedure Care
1. If the test is performed at the client's bedside, document on the client's medical record the result of the test, time, date, machine number, tube type or number, site of draw, and rate of infusion in units per hour if the client is receiving IV heparin.
Client and Family Teaching
1. Results are normally available within a few minutes.
Factors That Affect Results
1. Tests may be affected by hemodilution, poor operator technique, inadequate reagent-to-specimen mixture, improper storage of test kits, cardioplegic solutions, hypothermia, platelet dysfunction, hypofibrinogenemia, other coagulopathies, and certain medications.
2. In acute coronary conditions, such as unstable angina and acute myocardial infarction, baseline ACTs may be lower and heparin requirements higher, reflecting a thrombogenic state.
3. Heparinase-I (Neutralase) restores activated coagulation time in clients undergoing coronary artery surgery, as an alternative to protamine.
Other Data
1. Test cartridges available for the ACT II system: LR ACT, RACT, HR ACT, PT, GPC, and HTC. Test cartridges available for the Hemochron system are listed previously under Norms.
2. Heparin requirements as well as baseline ACTs vary from client to client, and so ACT determinations allow a quick titration of the effective heparin dose.
3. Therapeutic ACT values depend on several factors: type of ACT system, type of test tube and reagent, type of procedure being performed, clinical condition of client, and clinical preference of physician.
4. HemoTec and Hemochron ACT measurements cannot be used interchangeably.
Activated Partial Thromboplastin Substitution Test— Diagnostic
Norm.
Normal factors VIII, IX, X, XI, and XII.
Usage.
Helps identify single factor deficiencies causing prolonged partial thromboplastin time, including factors VIII, IX, XI, and XII.
Description.
A differential activated partial thromboplastin time (APTT) method that identifies which factor deficiency or deficiencies are present when APTT is prolonged. Known reagents for each factor are systematically added to the client's blood sample. A factor is determined to be deficient when the substitution produces a normal APTT.
Professional Considerations
Consent form NOT required.
Preparation
1. Tubes: Red topped and blue topped.
2. Preschedule the test with the laboratory.
Procedure
1. Draw 2-3 mL of blood into a red topped tube and discard. Completely fill a blue topped tube with the blood sample.
Postprocedure Care
1. Apply pressure over the venipuncture site for 5 minutes if the client is receiving heparin therapy. Observe the site closely for development of a hematoma.
2. Write the collection time on the laboratory requisition.
3. Refrigerate the specimen until the test is completed.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Failure to discard the first few milliliters of blood drawn may contaminate the specimen with tissue thromboplastin, which can activate coagulation.
2. Failure to completely fill the tube with blood may cause falsely prolonged results.
3. Hematocrit >50% may cause falsely prolonged results, and hematocrit <20 cause="" decreased="" falsely="" may="" p="" results.="">4. Drawing the sample from a line being kept open with a heparin flush will cause falsely prolonged results.
5. Reject hemolyzed specimens and specimens received more than 2 hours after collection.
6. Anticoagulant therapy within 2 weeks before the test invalidates results.
Other Data
1. Useful only with single-factor deficiencies.
2. See also Activated partial thromboplastin time and partial thromboplastin time—Plasma .
Activated Partial Thromboplastin Time (APTT) and Partial Thromboplastin Time (PTT)— Plasma
N ote : Activated partial thromboplastin time (APTT) is the current method of this test, which is still commonly referred to as “PTT.”
Norm.
Standardized times should be reported by each laboratory because results depend on the type of activator used. In general, standards are less than 35 seconds and vary by 20-36 seconds.
Premature infants <120 p="" seconds="">Newborn <90 p="" seconds="">Infants 24-40 seconds
Children 24-40 seconds
Adult panic level >70 seconds
Therapeutic Heparin Therapy Levels
Acute coronary artery disease 50-80 seconds
Peripheral vascular disease with embolism 50-80 seconds View full size
Panic Level Symptoms and Treatment
Symptoms.
Prolonged bleeding, hematoma at venipuncture site, cerebrovascular accident, hemorrhage, shock.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Assess heparin therapy.
2. Administer protamine sulfate (usual dose of 1 g of protamine sulfate for every 100 units of heparin).
3. Monitor vital signs.
4. Monitor for neurologic changes every hour until levels are within desired range.
Increased.
Major causes: Genetic or acquired deficiency of blood clotting factors IX, X, XI, or XII and with factor V or II deficiencies.
These deficiencies usually must be below 30%-40% of normal levels for clotting factors to produce increased APTT and bleeding tendencies as seen in hemophilia A. Longer times are associated with deficiencies of high molecular weight (HMW) kininogen and Fletcher factor (prekallikrein). Longer times also occur with abruptio placentae, afibrinogenemia, cardiac surgery, hypothermia, cirrhosis, disseminated intravascular coagulation, dysfibrinogenemia, fibrinolysis, Fitzgerald factor deficiency (severe), hemorrhagic disease of the newborn, hypofibrinogenemia, liver disease, hypoprothrombinemia, presence of circulating anticoagulants, lupus anticoagulant, and von Willebrand's disease and in clients receiving hemodialysis.
Drugs include alcohol, antistreplase (a thrombolytic agent), bishydroxycoumarin (excess therapy), chlorpromazine, codeine, eptifibatide, heparin calcium, heparin sodium, methotrexate, phenothiazines, salicylates, warfarin administration, and valproic acid.
Decreased.
Shortened times occur with abnormalities of Fletcher factor, which are not associated with bleeding and in which thromboemboli may occur. A shortened APTT (less than or equal to control) on presentation in clients with chest pain is associated with increased risk of acute MI.
Description.
Partial thromboplastin time (PTT) evaluates how well the coagulation sequence is functioning by measuring the amount of time it takes for recalcified, citrated plasma to clot after partial thromboplastin is added to it. The PTT is abnormal in 90% of coagulation defects and screens for deficiencies and inhibitors of all factors except VII and XIII. This test is most commonly used to monitor effectiveness of heparin therapy and to screen for disorders of coagulation. When commercial activating materials are used to standardize the test, the PTT is called the APTT, or “activated partial thromboplastin time.”
Professional Considerations
Consent form NOT required.
Preparation
1. For intermittent heparin dosing, the sample should be drawn 1 hour before the next dose. A baseline APTT may not be needed before heparin therapy unless disease is suspected.
2. Tube: 2.7- or 4.5-mL blue topped tube, a control tube, and a waste tube or syringe.
3. Do NOT draw specimens during hemodialysis.
4. Do NOT draw specimens from a closed-loop blood sampling system in an arterial line that uses heparin flush solution.
Procedure
1. Withdraw 2 mL of blood into a discard syringe or vacuum tube. Remove the syringe or tube, leaving the needle in place. Attach a second syringe, and draw a blood sample quantity of 2.4 mL for a 2.7-mL tube, or 4.0 mL for a 4.5-mL tube. Collect the sample without trauma.
Postprocedure Care
1. If the test cannot be performed within 2 hours after specimen collection, separate and freeze the plasma.
2. Transport the specimen to the laboratory immediately.
Client and Family Teaching
1. Surgery may be postponed if the results are prolonged.
2. Bleeding precautions for prolonged values include the following: use a soft toothbrush; use an electric razor; avoid aspirin or aspirin products; avoid constipation; wear loose clothing; avoid intramuscular injections.
3. Watch for and report signs of bleeding: bruising, petechiae, blood in stool/urine/sputum, bleeding from invasive lines, bleeding gums, abnormal or excessive vaginal bleeding.
4. Many herbs can cause bleeding effects. For this reason, do not take any herbal preparations or natural remedies without receiving your doctor's approval.
Factors That Affect Results
1. Do NOT draw samples from an arm into which heparin is infusing.
2. Failure to completely fill the tube will alter the results.
3. If you are drawing samples from an arterial line with a heparin-flush pressure bag, at least 10 mL of blood must be withdrawn before the PTT sample is drawn.
4. Failure to discard the first 1 to 2 mL of traumatic venous draw may result in a falsely decreased APTT.
5. A false-normal PTT may occur if factor levels are deficient but not less than 25% to 30% of normal.
6. Factor I (fibrinogen) deficiency may not be detectable unless levels are <100 dl.="" mg="" p="">7. Hematocrit >55% may cause falsely prolonged results. The test should be redrawn in a tube furnished by the laboratory that has had the concentration or amount of citrate adjusted for the elevated hematocrit level.
8. Freezing the sample will decrease the test sensitivity to lupus anticoagulant and to deficiencies of XII, XI, HMW kininogen, and prekallikrein.
9. Herbs or natural remedies that may increase PTT include dan shen (red-ginseng, Salvia miltiorrhiza ), dang gui [variants: tangkuei, dong quai] ( Angelica sinensis ) (in clients receiving warfarin concurrently), feverfew ( Tanacetum parthenium ), ginkgo biloba , ginger, and ginseng.
Other Data
1. 1 mg of protamine sulfate will reverse the effects of 100 units of heparin.
2. Hemophilia A causes increased APTT with normal PT and bleeding time.
3. Hemophilia B is diagnosed by increased APTT with normal or increased PT and direct assay of levels of factor IX.
4. APTT is not helpful in the diagnosis of hemophilia type.
5. APTT and PT are both increased with prothrombin and HMW kininogen and prekallikrein deficiencies.
6. Age, sex, and ABO blood group may have an influence on the APTT in normal clients.
7. Acceptable alternatives to APTT monitoring of direct anticoagulation thrombin inhibitors (DTIs) include the ecarin clotting time (ECT) and the thrombin inhibitor management (TIM) test.
Activated Protein C Resistance Test
See Protein C—Blood .
Acute Abdominal Series— Diagnostic
Norm.
Requires individual interpretation.
Usage.
Differential diagnosis of the cause of an acute condition of the abdomen. Some examples are abdominal aortic aneurysm dissection, abscess, acute cholecystitis, acute ischemia, acute pancreatitis, appendicitis, bile duct obstruction, bowel strangulation, choledocholithiasis, gastric outlet obstruction, perforated abdominal viscus, peritonitis, pyelonephritis, ruptured ectopic pregnancy, Salmonella enterocolitis, and ureteral obstruction. Also useful for identifying the presence and location of (a) foreign body(ies).
Description.
An acute abdominal condition is characterized by the abrupt onset of abdominal pain, distention, diminished or absent bowel sounds, and, sometimes, guarding. There may be many causes of these symptoms, and the disorder within the abdomen is hidden. In addition to a routine external physical assessment, seven routes of diagnostic work-up are used. Less invasive testing is usually performed initially.
Laboratory studies include coagulation studies, hemoglobin and hematocrit tests, and blood volume determinations to rule out internal bleeding, leukocyte differential to determine whether an infectious or inflammatory process is present, amylase level to rule out pancreatic and other pathologic conditions, liver panels to rule out a hepatic disorder, blood urea nitrogen and creatinine determinations and urinalysis to rule out urinary tract infection, and stool examination to rule out Salmonella . Fine-needle aspiration cytologic testing provides clues to the type of process occurring.
Plain-film radiography is taking a radiograph without the use of an injected radiopaque agent. Plain-film radiography of the abdomen may identify compression fractures, intestinal obstruction, metastasis, perforated abdominal viscus, pancreatic calcification, and renal calculi.
Contrast radiography involves injection of a radiopaque agent into the vascular space. The contrast agent enhances the appearance of organ and vascular lumens and is more likely to reveal a pathologic condition than is plain film radiography. Vascular contrast examinations of the abdominal area, such as intravenous pyelography, help identify lumbar aortic aneurysms, urinary tract trauma, lesions, or other disorders.
Intestinal contrast examinations such as barium enema, oral cholecystogram, and upper gastrointestinal series may identify colonic lesions or perforation but should not be performed when obstruction is suspected. They may also rule out appendicitis.
Ultrasonography may help diagnose acute abscesses, cholecystitis, Crohn's disease, dilated bile duct, hepatic cancer, hepatic or splenic hematoma, hydronephrosis, intussusception, pancreatitis, pancreatic pseudocyst, pancreatic carcinoma, splenomegaly, urinary tract obstruction, and the presence of foreign bodies.
Computed tomography helps identify, differentiate, and evaluate hepatic, pancreatic, renal, and retroperitoneal abscesses, fluid accumulations, masses and cysts, and pancreatitis.
Nuclear medicine studies help identify intra-abdominal abscesses, sites of gastrointestinal bleeding, hematoma, and areas of abnormal tissue metabolism. Nuclear medicine scans may also help to rule out cholecystitis.
In extremely acute situations and when findings from any combination of the above tests are inconclusive, surgical exploration of the abdomen may be required.
Professional Considerations
Consent form NOT required for the noninvasive studies. See individual listings for the invasive studies.
Risks
Allergic reaction to radiographic dye or nuclear medicine radiopharmaceutical for applicable tests (itching, hives, rash, tight feeling in the throat, shortness of breath, bronchospasm, anaphylaxis, death); renal toxicity.
Contraindications
Previous allergy to radiographic dye, iodine, or seafood or radionuclide for those tests involving injections; renal insufficiency.
Precautions
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk-benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dose to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.
Preparation
1. No preprocedural care is required for plain-film radiography.
2. Intestinal contrast examinations often require clear liquids the day before the test and cathartics with or without cleansing enemas before the test. However, this requirement may be waived for a client with acute abdominal symptoms.
3. Have emergency equipment readily available for tests involving injection of radionuclide or dye.
Procedure
1. Plain-film radiography: The client is positioned in supine, upright, oblique, and lateral decubitus positions, and radiographic films are taken from various angles. The best results are not obtained from portable films, especially in obese clients. The films should be taken in the radiology department, where the most powerful radiography is available, whenever possible. The lateral decubitus position is used for clients who are unable to stand, and the radiograph is taken horizontally across the table. A “kidneys, ureters, bladder film (KUB)” includes the majority of the abdomen and is taken from an anteroposterior angle. An anteroposterior scout film is used both before an intravenous pyelogram and in combination with an upright abdominal film for suspected intestinal obstruction. Subdiaphragmatic free air from a perforated abdominal viscus may be identified with an upright abdominal film or an upright chest film.
2. Vascular contrast examinations: Radiographic dye is injected into an arm vein, and oblique films of the abdomen are taken 15 minutes later. A left posterior oblique position may help identify a lumbar aortic aneurysm because the position enhances visualization by rotating the aorta off of the spine. Arteriography and venography may also help identify blood vessel abnormalities such as aneurysm, hemorrhage, or occlusion.
3. Intestinal contrast examination: The client is placed in a Sims' position. Barium, with or without air, is instilled into the lower gastrointestinal tract, and radiographic films are taken. In upper gastrointestinal series, the client must swallow barium, and radiographic films are then taken.
4. Ultrasonography: The client is positioned on the side or supine, and a series of high-frequency sound waves are transmitted into the abdomen. The echoes reflected from the differing tissue densities are converted by a gel-coated transducer to form patterns of the abdominal structures on an oscilloscope screen.
5. Computed tomography: The client is placed in a supine position on a platform table that moves the client through a circular computed tomography scanner. As several transverse films are taken, differing tissue densities are calculated based on varying absorption of the x-rays. Findings may indicate the need for further computed tomography after the administration of contrast medium.
6. Nuclear medicine studies: At varying intervals after the intravenous injection of a radioactive tracer, scintigraphic scans, which detect areas of increased concentration of the tracer at sites of a pathologic condition, are taken of the abdominal area.
Postprocedure Care
1. Fluids should be encouraged after studies involving the administration of radiopaque dyes or barium.
2. Cathartics may be prescribed after studies involving the administration of barium.
Client and Family Teaching
1. Explain the purpose of each test as appropriate, the procedure for the test, and the results. See individual test listings for specific client teaching.
Factors That Affect Results
1. The presence of gastrointestinal barium negates the value of plain-film radiography, vascular contrast examinations, ultrasonography, computed tomography, and nuclear medicine scintigraphy and so should be performed last.
Other Data
1. See also Barium enema—Diagnostic ; Flat-plate radiography of the abdomen—Diagnostic ; Intravenous pyelography—Diagnostic ; Upper gastrointestinal series—Diagnostic ; Computed tomography of the body—Diagnostic .
2. Health care professionals working in a nuclear medicine area must follow federal standards set by the Nuclear Regulatory Commission. These standards include precautions for the handling of the radioactive material and the monitoring of potential radiation exposure.
3. Some extra-abdominal conditions that may cause acute abdominal pain include pneumonia, pulmonary or myocardial infarction, and pericarditis. Other conditions that may cause symptoms of an acute abdominal condition include acute intermittent porphyria, diabetic neuropathy, heavy-metal poisoning, sickle cell disease, and tabes dorsalis.
Addis Count— 12-Hour Urine
Norm.
Erythrocytes 0-5,000/mm 3
Leukocytes 0-500,000/mm 3
Casts 1,000,000/mm 3 View full size
Increased.
Glomerulonephritis and hematuria.
Description.
When subclinical glomerulonephritis is suspected, an Addis count on a 12-hour urine specimen may demonstrate increased erythrocytes and leukocytes and increased rates of cast excretion in amounts too small to be detected in a random urine specimen examined microscopically. The count is performed on the sediment from a portion of the 12-hour collection.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a 1- or a 2-L bottle that has been rinsed in formalin.
Procedure
1. The clean-catch urine technique must be used to decrease the risk of specimen contamination. See clean-catch collection instructions in Body fluid, Routine—Culture .
2. Keep the specimen container refrigerated during and after specimen collection. For catheterized specimens, keep the drainage bag on ice and empty it into the collection container hourly.
Postprocedure Care
1. Send the entire 12-hour urine specimen to the laboratory.
Client and Family Teaching
1. Do not drink any fluids throughout the collection period.
2. Collect a clean-catch urine sample according to the technique described previously if this collection method is used.
Factors That Affect Results
1. Hematuria, pyuria, or a contaminated specimen will cause falsely elevated results.
Other Data
1. This test is not usually necessary when a thorough history and renal work-up are done.
2. An approximate Addis count can be performed on a first-morning voided specimen after a 16-hour fast from fluids and food.
Adenovirus Antibody Titer— Serum
Norm.
Negative. Results require interpretation with consideration of the site of the specimen correlated with clinical symptoms.
Current Adenovirus Infection.
Fourfold rise in titer.
Increased.
Adenovirus infection, respiratory failure, or graft failure in lung-transplanted clients. Gene therapy with replication-deficient adenoviral vector-mediated herpes simplex virus-thymidine kinase.
Description.
A group of virus types responsible for upper respiratory tract disease, hemorrhagic cystitis, and epidemic keratoconjunctivitis. The mode of transmission is by direct or indirect contact. Measurement of adenovirus antibody titers is the test of choice for detection of current adenovirus infections. Results are reported as the highest dilution of serum that completely neutralizes the virus.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 2-mL blood sample no later than 5-7 days after onset of symptoms.
2. After allowing the specimen to clot at room temperature, centrifuge and separate the serum into a separate vial.
3. Draw a convalescent sample in 14-21 days.
Postprocedure Care
1. Mark the tube label and laboratory requisition with “acute phase” or “convalescent phase” for the first and second specimens, respectively.
Client and Family Teaching
1. Return in 2-3 weeks to have the convalescent sample drawn.
Factors That Affect Results
1. Reject hemolyzed or frozen specimens.
2. Specimens may be stored several weeks at 4 to 6 degrees C.
3. Antibody titers for both specimens should be performed by the same laboratory.
Other Data
1. This test is nonspecific for the type of adenovirus present.
Adrenocorticotropic Hormone (ACTH, Corticotropin)— Serum
Norm.
SI Units
0800 hours, peak 25-100 pg/mL 25-100 ng/L
1800 hours, trough 0-50 pg/mL 0-50 ng/L
Random
Adult Male 7-69 pg/mL 7-69 ng/L
Adult Female 6-58 pg/mL 6-58 ng/L
Adolescent (10-18 yr) 6-55 pg/mL 6-55 ng/L
Child (up to 10 yr) 5-46 pg/mL 5-46 ng/L View full size
Increased.
Addison's disease, ectopic ACTH syndrome, pituitary adenoma, pituitary Cushing's syndrome, primary adrenal insufficiency, and stress. Drugs include amphetamine sulfate, calcium gluconate, corticosteroids, estrogens, ethanol, lithium carbonate, and spironolactone.
Decreased.
Primary adrenocortical hyperfunction (caused by tumor or hyperplasia) and secondary hypoadrenalism. Drugs include CPH 82—a nonsteroid antirheumatic drug.
Description.
ACTH is an anterior pituitary hormone that stimulates cortisol and androgen production by the adrenal gland. Diurnal variations of ACTH are typical, with peak levels occurring from 0600 to 0800 and trough levels occurring from 1800 to 2300.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Plastic or siliconized glass pink topped (containing K 2 EDTA) or plastic lavender topped, and ice-water slush.
2. See Client and Family Teaching .
Procedure
1. Draw a 3-mL blood sample at 0600. Repeat the sampling at 1800 if trough levels are needed.
2. Place the specimen in ice-water slush.
Postprocedure Care
1. Write the collection time on the laboratory requisition.
2. Transport the specimen to the laboratory immediately. The specimen should be frozen within 15 minutes if it will not be spun and tested within the first hour.
Client and Family Teaching
1. Consume a low-carbohydrate diet for 48 hours before the test.
2. Avoid physical and emotional stress for 12 hours before the test.
3. For peak and trough levels, two samples are required at different times of the day because the blood levels fluctuate throughout the day.
4. Results may take several days.
Factors That Affect Results
1. Reject specimens received more than 60 minutes after collection.
2. Values increase within 90 seconds of traumatic, repeated, or prolonged venipuncture.
3. Menstruation cycle, pregnancy, and radioactive scanning within 7 days affect ACTH levels.
4. This test may not detect certain types of synthetic ACTH.
Other Data
1. The ACTH stimulation test must be performed to confirm the diagnosis of Addison's disease.
ADT
See Respiratory Antigen Panel—Specimen .
AFB Smear
See Sputum, Mycobacteria—Culture and Smear .
AFP
See Alpha-Fetoprotein—Blood .
African Trypanosomiasis— Blood
Norm.
Negative. No parasites identified.
Positive.
African trypanosomiasis (African sleeping sickness).
Description.
Also known as sleeping sickness, African trypanosomiasis is a vector-borne parasitic infection indigenous to tropical Africa caused in humans by the bite of a tsetse fly of the genus Glossina . Symptoms include a chancre at the site of the bite, progressing to headache, fever, insomnia, anemia, rash, and lymph node swelling. After inoculation, trypanosomes invade all body organs. CNS symptoms appear in disease stage II. The course of the disease may run months to years and is frequently fatal with treatment and always fatal without treatment.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain an alcohol wipe, lancet, and capillary tube.
Procedure
1. Perform this procedure in the early afternoon, again at night, and when fever spikes occur.
2. Cleanse the pad of the index or second finger with the alcohol wipe and allow the fingerpad to dry.
3. Perform a finger stick and fill the capillary tube completely with blood. Quickly seal the capillary tube.
Postprocedure Care
1. Write on the laboratory requisition the name of the parasite suspected and the place(s) and date(s) of recent travel.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject clotted specimens.
2. Transport the capillary tube to the laboratory immediately for thick and thin smears to be performed before blood clots form.
Other Data
1. Person-to-person transmission of African trypanosomiasis is possible either by direct contact with infected blood or from mother to fetus. Pentamidine and suramin are used for early-stage disease, depending on the causative organism. Melarsoprol is the drug of choice for late-stage treatment. Eflornithine is better tolerated but difficult to administer, and Nifurtimox is inexpensive and can be administered orally but is not fully validated yet for use in humans.
2. African trypanosomiasis may cause myocarditis in some clients.
3. See also Trypanosomiasis serologic test—Blood ; Parasite screen—Blood .
AHI
See Polysomnography—Diagnostic .
AIDS Evaluation Battery
See Acquired Immune Deficiency Syndrome Evaluation Battery—Diagnostic ; T- and B-Lymphocyte Subset Assay—Blood .
Air Tonometry
See Tonometry Test for Glaucoma—Diagnostic .
ALA
See Antiphospholipid Antibodies—Serum .
Alanine Aminotransferase (ALT, Alanine Transaminase, SGPT)— Serum
Norm.
Adult 5-57 mU/mL
Adult Female 4-19 U/L or 10-30 Karmen U/mL or 317 nKat/L
Adult Male 7-30 U/L or 14-50 Karmen U/mL or 500 nKat/L
Children
<12 months="" span="" style="white-space: pre;">
≤ 54 U/L1-2 years 3-37 U/L
2-8 years 3-30 U/L
8-16 years 3-28 U/L View full size
Increased.
Anorexia nervosa, biliary tract obstruction, brain tumor, cerebrovascular accident (increased after 1 week), cirrhosis, congestive heart failure (with liver damage), delirium tremens, dermatomyositis, dysrhythmias, eating disorders (with liver impacted), Gaucher disease, hepatic cancer, hepatic damage, hepatitis (viral, toxic), hypercholesterolemia, hyperglycemia, hyperlipidemia, hypertension, hypertriglyceridemia, infectious mononucleosis, intramuscular injections, intestinal infarction, iron depletion, liver passive congestion, local irradiation injury, muscle injury (caused by electroshock, infection, seizure, or trauma), muscular dystrophy, myocardial infarction, myoglobinuria, Niemann-Pick disease, obesity, pancreatitis (acute), polymyositis, postoperatively (intestinal surgery), pulmonary infarction, renal infarction, Reye's syndrome, rhabdomyolysis, and shock with liver damage. Drugs include allopurinol, ampicillin, anabolic steroids, aspirin, barbiturates, bromocriptine mesylate, captopril, chlordiazepoxide, chlorpromazine hydrochloride, cinchophen, deferiprone, diphenylhydantoin, fosinopril, heparin (bovine, porcine) and statins. Herbal or natural remedies include chaparral tea (or misspelled chapparel tea, Larrea tridentata ), Echinacea , pennyroyal. Herbal or natural remedies that have the potential to cause hepatotoxicity and elevate values include akee fruit (ackee, Blighia sapida ), Atractylis gummifera, Azadirachta indica ( neem tree, margosa) , Berberis vulgaris (barberry), Callilepis laureola (blazing star, Liatris spicata ), chaparral tea ( Larrea tridentata ), cocaine, comfrey (“knitbone,” Symphytum officinale ), Crotalaria (bush tea), cycasin (a toxin from a Cycas species of sago palm of Guam), Echinacea , germander (genera Teucrium and Veronica ; do not confuse with “safe skullcap,” a name often falsely used in selling germander), Heliotropium (germander, valerian), jin bu huan (“gold-inconvertible”, Jin Bu Huan Anodyne Tablets, patent medicine with misidentified constituents: essence of t'ienchi [tianqi] flowers , “Notoginseng”; also kombucha ; also Lycopodium serratum , or club moss), m huang (Ephedra), margosa (Melia azadirachta, Azadirachta indica ), maté tea ( Ilex paraguayensis ), mistletoe, pennyroyal, sassafras, Senecio , skullcap ( Scutellaria ; do not confuse with “unsafe germander”), syo-saiko-to (xiao chai hu tang, “minor Bupleurum combination”), Teucrium polium (golden germander), and valerian ( Valeriana officinalis , garden heliotrope).
Decreased.
Steatosis in clients with hepatitis C and weight loss. Herbal or natural remedy is Chinese fructus schizandrae sinensis (wu wei zi, “five flavors herb,” Schisandra chinensis [Turcz.] Baill.).
Description.
Alanine aminotransferase (ALT) is an enzyme primarily produced by the liver and found in certain body fluids (such as bile, cerebrospinal fluid, plasma, and saliva) and in the heart, liver, kidneys, pancreas, and skeletal muscle. It acts as a catalyst in the transamination reaction that is necessary for amino acid production. This test is most commonly used to evaluate liver injury, where levels may rise to as much as 50 times normal range. The ALT levels are analyzed with aspartate aminotransferase (AST) levels to evaluate the degree of liver injury and to confirm a hepatic cause of AST increase. After the early stage of liver injury, ALT levels surpass AST levels. Serial measurements help track the course of hepatitis. This test may also be used by blood banks to screen for hepatitis in samples of donor blood.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List medications taken by the client within the last 3 days on the laboratory requisition.
3. Do NOT draw during hemodialysis.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. The specimen may be refrigerated but not frozen.
Client and Family Teaching
1. Results are normally available within 12 hours.
Factors that Affect Results
1. Hemolysis causes unreliable results.
2. Drugs that may cause falsely increased results include erythromycin, opiates, oxacillin sodium (Prostaphlin), and ampicillin (Polycillin).
3. Falsely decreased results may occur in beriberi, diabetic ketoacidosis, hemodialysis (chronic), liver disease (severe), and uremia or with coffee ingestion.
4. Herbal or natural remedies that may cause falsely decreased results include coffee ( Coffea ).
5. Serial norms generally vary by less than 10 U/L in the same healthy client.
Other Data
1. Older names for this test were glutamate-pyruvate transaminase and glutamic pyruvic transaminase.
Albumin–Serum, Urine, and 24-Hour Urine
Norm.
Nephelometric, calorimetric, and (combined) nephorimetric.
SI Units
Serum
Adult 3.5-5.0 g/dL 35-50 g/L
>60 years 3.4-4.8 g/dL 34-48 g/L
Average at rest 0.3 g/dL 3 g/L
Urine
Adult at rest 2-80 mg/24 hours 0.002-0.08 g/day
Adult, ambulatory <150 hours="" mg="" span="" style="white-space: pre;">
<0 .15="" day="" g="" p="">Child, <10 span="" style="white-space: pre;" years=""> <100 hours="" mg="" span="" style="white-space: pre;"> <0 .10="" day="" full="" g="" nbsp="" p="" size="" view="">Increased in Serum.
Dehydration, diarrhea, Hodgkin's disease, meningitis, metastatic carcinomatosis, multiple myeloma, myasthenia, neoplasms, nephrosis, nephrotic syndrome, non–Hodgkin's lymphoma, osteomyelitis, peptic ulcer, pneumonia, polyarteritis nodosa, pregnancy, protein-losing enteropathy, rheumatic fever, rheumatoid arthritis, sarcoidosis, scleroderma, sprue, steatorrhea, stress, systemic lupus erythematosus, trauma, tuberculosis, ulcerative colitis, uremia, vomiting, and water intoxication. Drugs include sulfobromophthalein (Bromsulphalein), cytotoxic agents, and oral contraceptives.
Increased in Urine.
Acute tubular necrosis, amyloid disease, anemia (severe), Bartter syndrome, Butler-Albright syndrome, Bright's disease, cardiac disease, central nervous system lesions, cerebrovascular accident, convulsions, cystitis, diabetes insipidus (nephrogenic), diabetic nephropathy, diphtheria, drug reaction, epididymitis, exercise, Fanconi syndrome, fever, galactosemia, glomerular lesion, glomerulonephritis, glomerulosclerosis, Goodpasture's syndrome, heavy-metal poisoning, hyperthyroidism, idiopathic thrombocytopenic purpura, intestinal obstruction, leukemia, liver disease, membranous nephropathy, multiple myeloma, nephritis, nephrosclerosis, nephrotic syndrome, pneumonia, poisoning (arsenic, carbon tetrachloride, ether, lead, mercury, mustard, opiates, phenol, phosphorus, propylene glycol, sulfosalicylic acid, turpentine), polycystic kidney disease, prostatitis, pyelonephritis (bacterial, chronic, hypertensive), renal radiation, renal tubular acidosis, renal vein thrombosis, scarlet fever, septicemia, streptococcal infection, subacute bacterial endocarditis, systemic lupus erythematosus, toxemia of pregnancy, tumor (abdominal, bladder, renal pelvis), typhoid fever, and Wilson's disease. Drugs include amphotericin B, ampicillin, ampicillin sodium, aspirin, bacitracin, barbiturates, cephaloridine, corticosteroids, gentamicin sulfate, gold, kanamycin, mercurial diuretics, neomycin sulfate, phenylbutazone, and polymyxin B.
Decreased in Serum.
Acute infection, alcoholism, ascites, atherosclerosis (advanced), beriberi, bone fractures, brucellosis, burns, cholecystitis, cirrhosis, congenital analbuminemia, congestive heart failure, Crohn's disease, cystic fibrosis, dementia, diabetes mellitus, edema, essential hypertension, glomerulonephritis, hemorrhage, hepatitis (viral), Hodgkin's dementia and disease, hyperthyroidism, infection, liver diseases, systemic lupus erythematosus (SLE), leukemia (lymphatic, monocytic, and myelogenous), lymphoma, macroglobulinemia, malabsorption syndrome, malnutrition, meningitis, metastatic carcinomatosis, multiple myeloma, myasthenia, myocardial infarction, neoplasms, nephrosis, nephrotic syndrome, osteomyelitis, peptic ulcer, pneumonia, polyarteritis nodosa, pregnancy, protein-losing enteropathy, rheumatic fever, rheumatoid arthritis, sarcoidosis, scleroderma, sepsis, sprue, steatorrhea, stress, stroke (with poor outcome), surgery, trauma, tuberculosis, ulcerative colitis, uremia, and water intoxication. Drugs include ampicillin, asparaginase, fluorouracil, and oral contraceptives.
Decreased in Urine.
Not clinically significant.
Description.
Albumin is one of the two main protein factions of blood. It functions in maintaining oncotic pressure and in transportation of bilirubin, fatty acids, drugs, hormones, and other substances that are insoluble in water. Protein is normally almost completely reabsorbed by the kidneys and undetectable in the urine. Therefore the presence of detectable albumin, or protein, in urine is indicative of abnormal renal function.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped for serum albumin.
2. Do NOT draw specimen during hemodialysis.
3. Obtain a 3-L specimen container without preservative for 24-hour urine albumin and write the beginning time of specimen collection on the container.
4. Obtain a clean specimen container for the spot urine specimen.
5. See Client and Family Teaching .
Procedure
1. Serum: Draw a 4-mL blood sample from an extremity that does not have intravenous fluids infusing into it (to avoid hemodilution and falsely low results). Avoid prolonged application of the tourniquet.
2. 24-hour urine: Collect all urine voided in a 24-hour period and refrigerate. For catheterized clients, keep the collection bag on ice, and empty it hourly into the collection container.
3. Spot urine collection may also be collected.
Postprocedure Care
1. Document the quantity of urine output and the ending time for the collection period on the laboratory requisition.
Client and Family Teaching
1. Consume a low-fat diet the day of the test.
2. Empty the bladder before starting 24-hour urine collection.
3. Save all urine voided in the 24-hour period, and urinate before defecating to avoid loss of urine. If any urine is accidentally discarded, discard the entire specimen and restart the collection the next day.
Factors That Affect Results
1. The results are invalid if the measurement is performed on plasma rather than serum.
2. Bromsulphalein testing within 2 days before specimen collection invalidates serum results.
3. Values are higher when upright or ambulatory. Serum values are higher after hemodialysis caused by fluid overload.
4. Falsely elevated urine results may be caused by contamination of the specimen with pus, menstrual blood, or vaginal discharge.
5. One study found a diurnal variation in urinary albumin levels in clients with insulin-dependent diabetes. Levels significantly increased between 2400 and 0800.
Other Data
1. A 24-hour urine collection for measuring protein loss may be helpful in clients with low serum albumin levels.
2. Increased levels in conjunction with a low glomerular filtration rate has been found through a 2011 meta-analysis (Gansevoort et al) to be associated with increased risk for renal problems such as acute and chronic kidney disease and end-stage renal disease.
3. Microalbuminuria in conjunction with metabolic syndrome is suggested to be a predictor for chronic kidney and heart disease ( Gobal et al, 2011 ).
Alcohol (Ethanol)— Blood
Norm.
Negative.
SI Units
Negative 0 mg/dL 0 mmol/L
Intoxication >100 mg/dL >22 mmol/L
Coma >300 mg/dL >65.1 mmol/L
Panic level 350-800 mg/dL 76.0-174.0 mmol/L View full size
Ethyl Alcohol (Ethanol) Poisoning Overdose Symptoms and Treatment
Symptoms
<50 dl="" mg="" span="" style="white-space: pre;"> Muscular incoordination50-100 mg/dL Worsening incoordination of movement
100-150 mg/dL Mood and behavior changes
150-200 mg/dL Delayed reactions
200-300 mg/dL Ataxia, double vision, nausea, vomiting
300-400 mg/dL Amnesia, dysarthria, hypothermia
400-700 mg/dL Respiratory failure, coma, death possible View full size
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Support oxygenation and protect airway.
2. Monitor for dehydration. Administer fluids as needed.
3. Hemodialysis WILL remove ethanol but is seldom necessary unless levels rise above 300 mg/dL. During hemodialysis, levels drop an average of 62 mg %/hour.
Increased.
Alcohol ingestion; concomitant use of alcohol and certain drugs (antihistamines, barbiturates, chlordiazepoxide, cyproheptadine, diazepam, glutethimide, guanethidine, isoniazid, meprobamate, opiates, phenytoin, tranquilizers); ethylene glycol poisoning; and ingestion of liniments, shaving lotion, astringents, elixirs, fluid extracts, tinctures, and cough medicines.
Description.
Alcohol (ethanol) is a central nervous system depressant with anesthetic and diuretic effects that is taken orally by clients. Ethanol is also used to treat methanol poisoning, and may be used prophylactically to prevent the occurrence of alcohol withdrawal symptoms.
Professional Considerations
Consent form NOT required unless the specimen may be used as legal evidence.
Preparation
1. Tube: Red topped, red/gray topped, gold topped, black topped, or lavender topped.
2. Do NOT draw during hemodialysis.
3. If a specific type of alcohol measurement is desired (methanol, isopropanol, ethylene glycol), list the specific alcohol on the laboratory requisition.
4. Screen client for the use of herbal preparations or natural remedies such as kava-kava ( Piper methysticum ) or ginseng.
Procedure
1. If the specimen is being collected for legal evidence, have the collection witnessed.
2. Cleanse the venipuncture site with povidone-iodine solution and allow it to dry.
3. Draw a 3-mL blood sample.
Postprocedure Care
1. If the specimen may be used for legal evidence, include the exact time of specimen collection on the tube label and sign and have the witness sign the laboratory requisition.
2. Transport the specimen to the laboratory in a sealed plastic bag labeled as legal evidence.
3. Each person handling the specimen should sign and record the time of receipt on the laboratory requisition.
Client and Family Teaching
1. Results are normally available within 24 hours.
2. Refer clients with intentional overdose for crisis intervention.
3. Referrals to appropriate rehabilitation centers and therapeutic community programs should be offered to all addicted clients who may be interested.
Factors That Affect Results
1. Cleansing the venipuncture site with an alcohol wipe may cause false-positive results.
2. Ginseng ( Panax spp.) increases alcohol clearance by increasing the activity of alcohol dehydrogenase and aldehyde dehydrogenase.
Other Data
1. Tolerance to alcohol's effects may develop in chronic alcoholics. Therefore, normally lethal levels may not lead to death in these clients.
2. Positive blood alcohol is associated with higher trauma severity in road accidents.
3. In hypothermia, the degree of ketosis is inversely proportional to blood ethanol concentration.
4. Men have significantly higher alcohol elimination rates compared to women.
5. Food intake increases alcohol elimination rates.
6. Only blood alcohol (rather than urine alcohol) levels are acceptable as legal evidence in most countries.
7. Postmortem alcohol levels may differ from sites including hematomas, blood, urine, and stomach contents.
8. Kava-kava ( Piper methysticum ), an herbal or natural remedy anxiolytic, potentiates the effects of ethanol.
9. The American College of Obstetricians and Gynecologists recommends annual blood alcohol screening women during the first trimester of pregnancy.
10. See also Toxicology, Volatiles group by GLC—Blood or urine .
Aldolase— Serum
Norm.
Adult
Ambulatory 1.0-7.5 U/L (30° C)
Bed rest 0.3-3.0 U/L (30° C)
Children
Newborn to 30 days 6.0-32.0 U/L
Age 1 month to 6 years 3.0-12.0 U/L
Age 7-17 years 3.3-9.7 U/L View full size
Increased.
Anemia (megaloblastic, hemolytic), burns, cancer, cirrhosis, congestive heart failure, crushing injury, dermatomyositis, Duchenne muscular dystrophy (early stages), eosinophilic fasciitis, erythroblastosis fetalis, hepatic necrosis, hepatitis (acute viral), hepatoma, jaundice (obstructive), lead intoxication, leukemia (chronic granulocytic), liver metastasis, lymphoma, metastasis, mononucleosis (infectious), muscle trauma, myocardial infarction (acute), myopathy, myositis, Niemann-Pick disease, pancreatitis (acute), pericarditis (hemorrhagic), polycythemia vera, polymyositis, prostate cancer, psychotic disorder, pulmonary infarction, skeletal muscle disease, surgical trauma, and trichinosis. Drugs include aminocaproic acid (large doses), carbenoxolone, chlorinated insecticides, clofibrate, corticotropin, cortisone acetate, cyclophosphamide (high dose), labetalol, organophosphorus insecticides, and thiabendazole.
Decreased.
Not clinically significant. Drugs include phenothiazines (when aldolase values are initially high in schizophrenics).
Description.
A group of isoenzymes (A, B, C) found throughout the body but in highest concentrations in skeletal muscle tissue, where aldolase is manufactured by myocytes. Because aldolase rises during active skeletal muscle disease, its measurement can help track the progress of diseases such as progressive muscular dystrophy, in which increases are seen in early stages, but levels fall as the disease progresses, reflecting lack of muscle ability to synthesize the aldolase enzyme. For most other muscle diseases, there are more specific tests available such as Creatine kinase—Serum; Alanine aminotransferase—Serum; and Aspartate aminotransferase—Serum. Norms for the isoenzymes are not established.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. Place the sample on ice for immediate transport to the laboratory.
Client and Family Teaching
1. Avoid strenuous exercise for 12 hours before sampling.
2. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject hemolyzed specimen to avoid falsely elevated results.
2. Recent intramuscular injections may elevate results.
Other Data
1. This test replaced by creatine kinase (CK) in muscular dystrophy.
Aldosterone— Serum and Urine
Norm.
Norms assume an average sodium diet (3 g/day).
Peripheral Blood Serum <16 span="" style="white-space: pre;">
SI Units <44 .8="" p="">Supine <16 dl="" ng="" span="" style="white-space: pre;"> <44 .8="" nmol="" p="">Upright
Adult Female
Pregnant 18-100 ng/dL 0.5-2.8 nmol/L
Nonpregnant 5-30 ng/dL 0.14-0.8 nmol/L
Adult male 6-22 ng/dL 0.17-0.61 nmol/L
Adrenal Vein 200-800 ng/dL 5.54-2.22 nmol/L
Child
<7 days="" span="" style="white-space: pre;"> 5-102 ng/dL 0.14-2.86 nmol/L7-21 days 6-179 ng/dL 0.17-5.01 nmol/L
1-11 months 7-99 ng/dL 0.20-2.77 nmol/L
1-2 years 7-93 ng/dL 0.20-2.60 nmol/L
3-10 years 4-44 ng/dL 0.11-1.23 nmol/L
>10 years <31 dl="" ng="" span="" style="white-space: pre;">
<0 .86="" nmol="" p="">Urine
Normal-sodium diet (100-200 mEq) 6-25 µg/24 hours 16.8-70.0 nmol/day
Low-sodium diet (<25 meq="" span="" style="white-space: pre;"> 17-44 µg/24 hours 4.76-123.3 nmol/dayHigh-sodium diet (>200 mEq) 0-6 µg/24 hours 0-16.8 nmol/day View full size
Increased in Serum and Urine.
Adrenal tumor (aldosterone-producing adenoma), aldosteronism (primary, secondary), bilateral adrenal hyperplasia, cirrhosis, congestive heart failure, Conn's syndrome, hemorrhage, hypertension (essential, >140/90 mm Hg), hyponatremia, hypovolemia, idiopathic cyclic edema, nephrosis (lower nephron), nephrotic syndrome, and renovascular hypertension. Drugs that increase serum levels include angiotensin-converting enzyme (ACE) inhibitors, corticotropin, diuretics that promote sodium excretion, estrogens, laxatives that are abused, some oral contraceptives, and potassium. Drugs that increase urine levels include angiotensin, deoxycorticosterone, diuretics (loop, thiazide), etiocholanolone, oral contraceptives, and steroids.
Decreased in Serum and Urine.
Addison's disease, preeclampsia, primary hypoaldosteronism, salt-wasting syndrome, septicemia, stress, and toxemia of pregnancy. Herbal or natural remedy is licorice. Drugs that decrease serum levels include aminoglutethimide, ACE inhibitors, deoxycorticosterone, etomidate, fludrocortisone, heparin (after several days of continuous therapy), indomethacin, methyldopa, and saralasin. Drugs that decrease urine levels include aminoglutethimide, clonidine, deoxycorticosterone, fludrocortisone, glucocorticoids, labetalol, heparin, methyldopa, metyrapone, and propranolol.
Description.
Aldosterone is a mineralocorticoid secreted by the adrenal cortex that functions in blood pressure and body fluid regulation. It acts on the renal distal tubules, causing increased resorption of sodium and water and increased excretion of potassium.
Professional Considerations
Consent form NOT required.
Preparation
1. The client should rest in a supine position for 8-12 hours. The sample should be drawn before noon.
2. Tube: Red topped, red/gray topped, gold topped, lavender topped, or green topped for serum collection.
3. For urine test, obtain a 3-L container (to which 10 g of boric acid has been added) and a 100-mL specimen container for urinary sample.
4. See Client and Family Teaching .
Procedure
Serum Test
1. Collect 2.5-mL blood sample for serum aldosterone.
Urine Test
1. Discard the first morning-urine specimen.
2. Collect all urine voided in a 24-hour period in a refrigerated container to which 10 g of boric acid has been added. Include urine voided at the end of the 24-hour period. For catheterized clients, keep the drainage bag on ice and empty the urine into the collection container hourly.
3. At the end of 24 hours, mix the urine gently and collect a 100-mL aliquot in a clean container.
Postprocedure Care
1. Note total 24-hour urine volume on the laboratory requisition and the aliquot container label.
2. Transport the 24-hour and aliquot samples to the laboratory immediately.
Client and Family Teaching
1. Follow a 3-g/day sodium diet for 2 weeks if not contraindicated by medical condition.
2. Avoid physical or psychologic stress throughout the collection period.
3. Save all urine voided in the 24-hour period, urinate before defecating to avoid loss of urine, and avoid contaminating the specimen with feces or soiled tissue. If any urine is accidentally discarded, discard the entire specimen and restart the collection the next day.
4. Results may not be available for several days.
Factors That Affect Results
1. Radioactive scans within 7 days before urine collection invalidate the results.
2. Hemolysis invalidates the serum results.
3. Decreased kidney perfusion may cause increased aldosterone and renin values.
4. Levels may be suppressed in clients with insulin-dependent diabetes mellitus.
5. An upright client position for serum collection invalidates the results. Changes in urine aldosterone are not affected by body position.
Other Data
1. Serum electrolyte and renin levels should be measured before this test.
Aldosterone Suppression Test— Diagnostic
Norm.
<5 dl="" ng="" nmol="" p="" si="" units="">
Primary Aldosteronism.
>10 ng/dL (>0.2777 nmol/L SI units).
Usage.
Definitive diagnosis of primary aldosteronism, which is also common in clients with essential hypertension.
Description.
Aldosterone is a mineralocorticoid secreted by the adrenal cortex that functions in blood pressure and body fluid regulation. It acts on the renal distal tubule, where it increases resorption of sodium and water at the expense of increased potassium excretion. Levels are affected by body position and sodium and potassium levels. The aldosterone suppression test measures aldosterone levels before and after an infusion of saline. In primary aldosteronism, the saline infusion fails to suppress aldosterone levels as much as it suppresses the levels in a normal client.
Professional Considerations
Consent form NOT required.
Risks
Volume overload, hypertension, myocardial ischemia, congestive heart failure.
Contraindications
The serum test is contraindicated in clients with congestive heart failure.
Preparation
1. The client should be positioned upright for 2 hours and then lie in a recumbent position from the onset of the test until the second specimen is drawn at the completion of the infusion.
2. Tubes: Two red topped, red/gray topped, gold topped, green topped, or lavender topped for blood test.
3. Obtain 2 L of 0.9% saline and a 24-hour urine collection container to which 10 g of boric acid has been added.
Procedure
Serum Collection
1. Draw a 2.5-mL blood sample for the baseline aldosterone level.
2. Infuse 2 L of normal saline intravenously over a 4-hour period to the recumbent client.
3. Draw a final 2.5-mL blood sample for aldosterone level.
Urine Collection
1. Discard the first morning-urine specimen.
2. Collect all urine voided in a 24-hour period in a refrigerated container to which 10 g of boric acid has been added. Include urine voided at the end of the 24-hour period. For catheterized clients, keep the drainage bag on ice and empty the urine into the collection container hourly.
3. At the end of 24 hours, mix the urine gently and collect a 100-mL aliquot in a clean container.
Postprocedure Care
1. Note the collection site and the time on all laboratory requisitions and blood tubes. For the urine sample, write the total 24-hour urine volume on the laboratory requisition and the aliquot container label.
2. Transport each specimen to the laboratory immediately after collection.
Client and Family Teaching
1. The test takes several hours. Bring reading material or other diversional item.
2. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Radioactive scans within 7 days before urine collection invalidate results.
3. Cimetidine, but not omeprazole, inhibits test results.
Other Data
1. Insulin resistance occurs with primary hyperaldosteronism.
Alkaline Phosphatase, Heat Stable— Serum
Norm.
Interpreted by laboratory. Results are reported as the percentage of alkaline phosphatase that is heat stable. Residual activity <30 and="" favors="" hepatic="" origin="">30% favors bone origin
Usage.
Aids in differentiation of the source of increased alkaline phosphatase activity. Decreased in premature uterine contractility in women in second trimester. Diagnosis and treatment monitoring for breast cancer, squamous cell carcinoma of the head and neck, and leukemia.
Description.
Alkaline phosphatase is an enzyme normally found in bone, liver, intestine, and placenta that rises during periods of bone growth (osteoblastic activity), liver disease, and bile duct obstruction. It is made up of bone, liver, and placental and intestinal isoenzymes that can be separated by heat fractionation. Liver and placental alkaline phosphatase isoenzymes are heat stable, and bone isoenzyme is inactivated by heat. Greater than 30% of the alkaline phosphatase being heat stable is suggestive of activity of liver origin, whereas <30 activity="" being="" bone="" heat="" is="" of="" origin.="" p="" stable="" suggestive="">
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Do NOT draw during hemodialysis.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory immediately for testing or for spinning and refrigeration.
Client and Family Teaching
1. The client may be asked to fast for 10-12 hours.
2. Results may take several days.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Hepatotoxic drugs within 12 hours before specimen collection invalidate the test.
3. Failure to fast before the test may result in falsely elevated levels.
4. Specimens left at room temperature may result in falsely elevated levels.
Other Data
1. Postmenopausal females have slightly increased total alkaline phosphatase levels and a low percentage of heat-stable fraction, indicating osseous origin.
Alkaline Phosphatase, Isoenzymes
See Alkaline Phosphatase—Serum .
Alkaline Phosphatase— Serum
Norm.
Total Alkaline Phosphatase SI Units
King-Armstrong Method
Adults, 20-60 years 4.5-13 U/dL or 39-117 mU/mL 32-92 U/L
Elderly Slightly higher
Newborn 5-15 U/dL 36-107 U/L
Premature newborn: 1.5-2 times adult value
Children: Values remain high until epiphyses close
1 month 10-30 U/dL 71-213 U/L
3 years 10-20 U/dL 71-142 U/L
10 years 15-30 U/dL 107-213 U/L
Bodansky Method
Adults, 20-60 years 2-4 U/dL 10.7-21.5 U/L
Elderly Slightly higher
Children 5-14 U/dL 27-75 U/L
Bessey-Lowry-Brock Method
Adults, 20-60 years 0.8-2.3 U/dL 13.3-38.3 U/L
Elderly Slightly higher
Bowers and McComb Method
Females
1-12 years <350 span="" style="white-space: pre;" u="">
<5 .95="" at="" p="">Puberty: Values may triple
>15 years 25-100 U/L 0.43-1.70 µKat/L
Males
1-12 years <350 span="" style="white-space: pre;" u=""> <5 .95="" at="" p="">12-14 years <500 span="" style="white-space: pre;" u=""> <8 .50="" at="" p="">Puberty: Values may triple
>20 years 25-100 U/L 0.43-1.70 µKat/L View full size
Isoenzyme Norms (Isoenzyme Inactivated after 16 Minutes at 55 degrees C)
Heat Inactivation Method Percentage Fraction
Liver isoenzyme 50-700 0.50-0.70
Bone isoenzyme 90-100 0.90-1.00
Intestinal isoenzyme 50-600 0.50-0.60
Placental isoenzyme: Trimester 1 to 1 month postpartum 50% of total View full size
Increased Biliary Isoenzyme.
Biliary cirrhosis, biliary duct obstruction, cholangio-hepatitis, and cholestasis.
Increased Bone Isoenzyme.
Bone cancer accompanied by bone formation, bone growth or healing, familial hyperphosphatemia, familial osteoectasia, Gaucher disease, growth hormone overproduction, hyperparathyroidism, hyperthyroidism, leukemia of bone marrow, lymphoma, malabsorption, myositis ossificans, Niemann-Pick disease, osteoblastic metastases, osteogenesis imperfecta, osteomalacia, osteoporosis, osteogenic sarcoma, Paget's disease, polyostotic fibrous dysplasia, renal osteodystrophy, and rickets.
Increased Intestinal Isoenzyme.
Gastrointestinal disease, clients with blood type O or B (some), pancreatic duct obstruction, pancreatic cancer, splenic infarction, steatorrhea (idiopathic), and ulcer (perforated).
Increased Liver I Isoenzyme.
Impaired enzyme metabolism, liver congestion, hepatic carcinoma, hepatotoxic drugs, jaundice (obstructive), pregnancy, and vasculitis.
Increased Liver II Isoenzyme.
Hepatitis (infectious, viral), parenchymal cell damage.
Increased Placental Isoenzyme.
Pregnancy (late).
Increased Total Alkaline Phosphatase.
May also be caused by alcoholism, carbohydrate ingestion (large quantities), children known to have increased values, cholelithiasis in persons with sickle cell disease, diabetes mellitus, Fanconi syndrome, fat ingestion, fibrous dysplasia, histiocytosis, Hodgkin's disease, hyperalimentation, hyperparathyroidism (with bone disease), hyperthyroidism, hypophosphatemia, kidney tissue rejection, liver abscess, liver disease, lung cancer, lymphoma, mononucleosis (infectious), multiple myeloma, myocardial infarction, osteosarcoma, primary biliary cirrhosis, pulmonary infarction, renal infarction, rheumatoid arthritis, rickets, sarcoidosis, and sickle cell crisis. Drugs include acetaminophen, acetohexamide, acyclovir, albumin, allopurinol, aluminum nicotinate, amiodarone, amitriptyline, ampicillin, anabolic steroids, androgens, asparaginase, aspirin, aurothioglucose, azathioprine, baclofen, barbiturates, bromocriptine mesylate, carbamazepine, carmustine, cephalexin, cephaloridine, chlordiazepoxide, chlorpromazine hydrochloride, chlorpropamide, cholestyramine resin, cimetidine, cinchophen, clindamycin, clonazepam, colchicine, diltiazem, ergosterol, erythromycin, estrogens, floxuridine, flurazepam, fosinopril, gold sodium, N-hydroxyacetamide, imipramine, imipramine pamoate, indomethacin, isoniazid, lincomycin, meclofenamate sodium, methotrexate, methyldopa, methyldopate hydrochloride, methyltestosterone, metoprolol tartrate, minoxidil, mithramycin, naproxen sodium, niacin, nifedipine, nitrofurantoin, novobiocin, oral contraceptives, oxacillin sodium, oxyphenisatin, papaverine hydrochloride, penicillamine, pertofrane, phenobarbital, phenothiazines, phenylbutazone, phenytoin, procainamide hydrochloride, propranolol, propylthiouracil, rifampin, salicylates, sildenafil, sulfamethoxazole, sulfisoxazole, sulfisoxazole acetyl, sulfobromophthalein sodium, tetracycline, thiomalate, thiothixene, thyroid hormone replacement, tolazamide, tolbutamide, tolmetin sodium, valproic acid, and vitamin D. Herbal or natural remedies include Echinacea (taken for 8 weeks or longer).
Decreased.
Anemia (pernicious), blood transfusions (massive), celiac disease, cretinism, hypophosphatasia, hypothyroidism, malnutrition, milk-alkali syndrome (Burnett's syndrome), nephritis (chronic), osteolytic sarcoma, scurvy, vitamin D intoxication, and zinc depletion. Drugs include aminobisphosphonates (Neridronate), edetate disodium, fluorides, oxalates, phosphates, and propranolol.
Description.
Alkaline phosphatase is an enzyme found in bone, liver, intestine, and placenta that rises during periods of bone growth (osteoblastic activity), liver disease, and bile duct obstruction. It is made up of bone, liver, placental, biliary, and intestinal isoenzymes that can be separated by electrophoresis. Alkaline phosphatase isoenzymes should be measured for any client who has an elevated alkaline phosphatase level.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate testing or for spinning and refrigeration.
Client and Family Teaching
1. Client may be asked to fast for 10-12 hours.
2. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Hepatotoxic drugs within 12 hours before collection invalidate the test.
3. Falsely elevated results may be caused by failure to fast before the test or by specimens left at room temperature.
4. Echinacea taken for 8 weeks or longer may cause hepatotoxicity.
Other Data
1. Isoenzymes are required to interpret the contributing source (liver, bone, placenta) of elevated total alkaline phosphatase.
2. At least 2 days are required for isoenzyme results.
3. Differentiation of bone and liver isoenzymes is difficult, because both are derived from a single gene. A monoclonal antibody assay that may aid in differentiation of liver and bone isoenzymes is being tested.
4. Studies have shown that some statins have been shown to decrease bone-specific alkaline phosphatase, but results are not yet conclusive.
Allergen-Specific IgE— Serum
Norm.
<2 immunoglobulins.="" nbsp="" of="" p="" serum="">
Adults <41 ml="" p="" u="">Children
Neonate <12 ml="" p="" u="">1-3 years <10 ml="" p="" u="">4-6 years <24 ml="" p="" u="">7-8 years <46 ml="" p="" u="">9-12 years <116 ml="" p="" u="">13-14 years <63 full="" ml="" nbsp="" p="" size="" u="" view="">Increased.
Allergic rhinitis, anaphylaxis, asthma (exogenous), atopic dermatitis, atopic eczema, Echinococcus infestation, eczema, hay fever, hookworm disease, latex allergy, schistosomiasis, and visceral larva migrans. Drugs include aminophenazone, anticonvulsants, asparaginase, hydralazine hydrochloride, oral contraceptives, and phenylbutazone.
Decreased.
Asthma (endogenous), pregnancy, and radiation therapy. Drugs include methotrexate.
Description.
Immunoglobulin E (IgE) is a protein produced in the bone marrow that functions as an antibody in response to antigen stimulation in hypersensitivity reactions. IgE levels are influenced by the nature of the allergen, length of exposure to the allergen, symptomatic responses, and hyposensitization treatments. The test is performed by radioimmunoassay.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List vaccinations, immunizations, and tetanus antitoxin received within the previous 6 months on the laboratory requisition.
3. List the blood products the client received within 6 weeks before the test on the laboratory requisition.
Procedure
1. Draw a 3-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory immediately.
Client and Family Teaching
1. Fast, except for water, for 12-14 hours before the test.
2. Results are normally available within 24 hours.
3. Refer the client with elevated IgE levels and allergic symptoms to an allergist for more specific testing and guidance on potential treatments and environmental reduction of allergens.
Factors That Affect Results
1. A delay in testing invalidates results.
2. Results are invalidated if the client has undergone a scan using a radioisotope within 1 week before the test.
Other Data
1. This test is often used to accompany a negative radioallergosorbent test (RAST) to assess for reactivity to untested allergens.
2. A newer serum test under investigation to determine its sensitivity is the multiple antigen simultaneous test (MAST), which can simultaneously detect allergies to up to 3.5 allergens in one serum sample.
3. See also Allergen-Specific IgE antibody—Serum ; Skin test for hypersensitivity—Diagnostic .
Allergen-Specific IgE Antibody (RAST Test, Radioallergosorbent Test, Allergy Screen)— Serum
Norm.
Negative.
ImmunoCAP FEIA method.
<0 .35="" ku="" nbsp="" p="">
Pharmacia CAP system
Asymptomatic Clients Symptomatic Allergy
Perennial allergens ≤ 10.7 kU/L >10.7 kU/L
Seasonal allergens ≤ 8.4 kU/L >8.4 kU/L
All allergens ≤ 11.7 kU/L >11.7 kU/L View full size
Results Reported by Allergen Scores on 0-4 Scale
0 No IgE detected
1 Borderline
2-4 Increasing levels of IgE View full size
Modified RAST
Class Counts Significance
0-749 No specific IgE activity
1 750-1,600 Borderline activity
2 1,601-3,600 Low positive
3 3,601-8000 Moderate positive
4 8,001-18,000 High positive
5 18,001-40,000 Very high positive
6 >40,000 Extreme high positive View full size
Usage.
Helps with differential diagnosis of allergies (especially food allergies of the immediate type), atopic asthma, natural rubber latex allergies, and psoriasis; monitoring of treatment for specific allergies.
Description.
This test measures the amount of IgE directed against specific allergens by binding a specific antigen to a carrier substance and allowing it to react with a specific IgE antibody in the client's blood sample. The amount of bound IgE is then measured. The test is used to identify allergies to foods, grasses, weeds, trees, molds, epidermals, insects, and miscellaneous substances such as house dust, insulin, latex, and silk. An advantage of this test is that one can obtain the information without causing an allergic reaction because the allergen is introduced into the blood sample rather than into the body.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning, serum separation, and refrigeration of serum.
Client and Family Teaching
1. Results may take several days.
Factors That Affect Results
1. IgE levels are influenced by the nature of the allergen, length of exposure to the allergen, symptomatic responses, and hyposensitization treatments.
2. Results are invalidated if the client received radioactive dyes within 7 days before the test.
3. False-positive results may be caused by high IgE levels (>3000 U/mL) attributable to parasitic infection.
Other Data
1. This test correlates 80% to 85% with subcutaneous skin testing and is more specific.
2. A total IgE level should also be obtained. If the RAST test is negative but total IgE level is elevated, the allergen may not be one for which the RAST test can be used.
3. See also Allergen-Specific IgE—Serum ; Skin test for hypersensitivity—Diagnostic .
Allergy Screen
See AllergenSpecific IgE Antibody—Serum .
Allergy Skin Test
See Skin Test for Hypersensitivity—Diagnostic .
Alpha 1 -Antitrypsin— Serum
Norm.
85-215 mg/dL (15.64-39.56 µmol/L, SI units.)
Increased.
Alzheimer's disease, cholangiocarcinoma, emphysema, hepatitis, hepatocholangiocarcinoma, hyaline membrane disease, hypercholesterolemia, infection, inflammation (acute, chronic), liver disease (chronic), neoplasm, pregnancy, sepsis, systemic lupus erythematosus, and ulcerative colitis. Drugs include estrogens, oral contraceptives, and steroids.
Decreased.
Congenital alpha 1 -antitrypsin deficiency, chronic obstructive pulmonary disease, emphysema, and liver disease (chronic) and in newborns (transient).
Description.
A major faction of alpha 1 -globulin protein detected by serum protein immunoelectrophoresis. Alpha 1 -antitrypsin is a serine proteinase inhibitor that functions in protection of body fluids by inactivating neutrophil elastase, a byproduct of lung inflammatory or infectious processes. The test is used to screen for clients at high risk for emphysema and liver disease associated with a congenital absence of the protein. Clients who have symptoms of cough, dyspnea or wheezing, in conjunction with a smoking history, should be evaluated for COPD using this test and spirometry. Other uses for this test include nonspecific detection of inflammatory, infectious, and necrotic processes.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Freeze the specimen.
Client and Family Teaching
1. The client with hypercholesterolemia or hyperlipemia should fast 8-10 hours.
2. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject hemolyzed specimens.
Other Data
1. Levels may also be measured in amniotic fluid.
Alpha-Fetoprotein (AFP)— Blood
Norm.
Tumor marker <8 .5="" ml.="" ng="" p="">
(See also Amniocentesis and Amniotic fluid analysis—Diagnostic, for fetal values )
SI Units
Nonpregnant Female 0-15 ng/mL 0-15 µg/L
Pregnant
2 months <75 ml="" ng="" span="" style="white-space: pre;"> <75 g="" p="">3 months <130 ml="" ng="" span="" style="white-space: pre;"> <130 g="" p="">4 months <210 ml="" ng="" span="" style="white-space: pre;"> <210 g="" p="">5 months <300 ml="" ng="" span="" style="white-space: pre;"> <300 g="" p="">6 months <400 ml="" ng="" span="" style="white-space: pre;"> <400 g="" p="">7 months <450 ml="" ng="" span="" style="white-space: pre;"> <450 g="" p="">8 months <450 ml="" ng="" span="" style="white-space: pre;"> <450 g="" p="">9 months <400 ml="" ng="" span="" style="white-space: pre;"> <400 g="" p="">Immediately postpartum <375 ml="" ng="" span="" style="white-space: pre;"> <375 g="" p="">Adult Males 0-15 ng/mL 0-15 µg/L
Children
Premature Infant Up to 158,000 ng/mL Up to 158,000 µg/L
Full-term Infant
0-14 days 5000-105,000 ng/mL 5000-105,000 µg/L
2 weeks–1 month 100-10,000 ng/mL 10-10,000 µg/L
2 months 40-1000 ng/mL 40-1000 µg/L
3 months 11-300 ng/mL 11-300 µg/L
4 months 5-200 ng/mL 5-200 µg/L
5 months 0-90 ng/mL 0-90 µg/L
≥6 months 0-15 ng/mL 0-15 µg/L View full size
Increased.
Ataxia telangiectasia, Beckwith-Wiedemann syndrome (child), cirrhosis, gonadal teratoblastoma, cancer (embryonal, hepatoblastoma, hepatocellular [primary], lung, pancreatic with liver metastases, malignant teratoma of ovary or testes, gastric with liver metastases, biliary system, germ cell tumors), hemangioendothelioma, hepatitis (viral) (acute, chronic, neonatal), liver metastasis from gastric cancer, pregnancy (with fetal neural tube defects, multiple fetuses, fetal distress, fetal death, intrauterine death, duodenal atresia, omphalocele), pure seminoma, spontaneous abortion, spontaneous preterm birth in pregnant women 24-28 weeks of gestation, tetralogy of Fallot (or Turner's syndrome), tyrosinemia, and ulcerative colitis.
Decreased.
Has been associated with Down syndrome when less than 0.25 times the normal median, associated with high birth weight with very low second-trimester levels. Drugs include protease inhibitors in females infected with human immunodeficiency virus.
Description.
A globulin protein secreted by liver cells during hepatic cell multiplication and found in high amounts in fetal plasma. Highest adult amounts are found during pregnancy and in primary hepatic cancer. Maternal levels should be measured initially at 15-18 weeks of gestation as a screening method for fetal neural tube defects. Confirmatory testing (for levels greater than 0.5-2.5 times the normal median) should be repeated in 7 days. For positive confirmatory test, ultrasonography and amniotic fluid AFP measurement should be performed. Used as a tumor marker, the AFP level is most specific when concentrations are >1000 ng/mL.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List on the laboratory requisition: maternal weight, maternal race, weeks of gestation, and any history of diabetes mellitus.
Procedure
1. Draw a 4-mL blood sample from the mother.
Postprocedure Care
1. Apply a dry, sterile dressing over the amniocentesis site.
Client and Family Teaching
1. Results may take several days.
Factors That Affect Results
1. Normal levels are affected by the mother's age, weight, and number of fetuses present.
2. Reject hemolyzed specimens.
3. Results are invalid if the client has undergone a radioisotope scan within the previous 2 weeks.
4. Protease inhibitors are associated with lower AFP levels in women who are infected with HIV.
Other Data
1. AFP testing may also be performed on amniotic fluid to detect neurologic congenital defects and Down syndrome. Serum AFP measurement is believed to increase accuracy of antenatal detection of Down syndrome from 35% to 67%, but its accuracy can be affected by maternal weight, smoking history, and diabetes mellitus and by whether the gestational age of the fetus is correctly estimated.
2. AFP is not a screening test for cancer.
3. AFP is insensitive for the diagnosis of hepatocellular carcinoma in African-Americans.
ALT
See Alanine Aminotransferase—Serum .
Alternate Pathway Factor B
See C3 Proactivator—Serum .
AMA
See Antimitochondrial Antibody—Blood .
Amikacin Sulfate— Blood
Norm.
SI Units
Therapeutic peak 20-25 mg/L or µg/mL 34-43 µmol/L
Toxic peak >35 mg/L or µg/mL >60 µmol/L
Therapeutic trough 5-10 mg/L or µg/mL 9-17 µmol/L
Toxic trough (adult) >10 mg/L or µg/mL >17 µmol/L
Toxic trough (child) >5 ng/mL >9 µmol/L View full size
Toxic Level Symptoms and Treatment
Symptoms.
Ototoxicity, nephrotoxicity.
Treatment
N ote : Treatment choices depend on client's history and condition and episode history.
1. Stop drug.
2. Monitor amikacin levels.
3. Monitor serum urea nitrogen and creatinine levels every day.
4. Perform eighth cranial nerve assessments every day.
5. Both hemodialysis and peritoneal dialysis WILL remove amikacin.
Increased.
Aminoglycoside toxicity and impaired renal function.
Decreased.
Subtherapeutic levels in client treated with aminoglycoside.
Description.
Amikacin is a semisynthetic aminoglycoside antibiotic derived from kanamycin and effective against gram-negative and gram-positive organisms. It is excreted by glomerular filtration, with a half-life of 1.9-2.8 hours. Peak and trough levels should be monitored throughout therapy. Toxicity is possible at trough levels. Steady-state levels are reached after 10-15 hours. Effective in gram-positive bacteremia in childhood and the treatment of ventilator-associated pneumonia.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Do NOT draw during hemodialysis.
3. Write the time, dose, and route of the most recent dose on the laboratory requisition.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Cross-reactivity may occur with concomitant antibiotic therapy (cephalosporin, chloramphenicol, clindamycin, kanamycin, penicillin, tetracycline, tobramycin).
Other Data
1. Potentially nephrotoxic, irreversibly ototoxic, and neurotoxic.
2. Creatinine clearance should be monitored every day for clients receiving amikacin.
3. Hypoalbuminemia correlates strongly with amikacin nephrotoxicity.
Amino Acid Screen
See Dinitrophenylhydrazine Test—Diagnostic .
Aminophylline
See Theophylline—Blood .
Amiodarone— Plasma or Serum
Norm.
Negative.
SI Units
Therapeutic 0.5-2.5 µg/mL 0.8-3.9 µmol/L level
Panic level >2.5 µg/mL >3.9 µmol/L View full size
For samples tested >24 hours after collection, see Factors That Affect Results .
Panic Level Symptoms and Treatment
Symptoms.
Bronchial asthma, heart failure, hepatic dysfunction, hyponatremia, jaundice, pulmonary fibrosis (irreversible), syndrome of inappropriate antidiuretic hormone, thyrotoxicosis.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Provide respiratory and hemodynamic support.
2. Discontinue medication.
3. Provide continuous ECG monitoring to identify reappearing dysrhythmias and bradycardia.
4. Use a transcutaneous pacemaker (prophylactically for sinus arrest).
5. Induce emesis (cautiously) soon after ingestion.
6. Tap water or warm saline lavage may be added.
7. Administer activated charcoal, saline, or sorbitol cathartic.
8. Hemodialysis and peritoneal dialysis will NOT remove amiodarone.
Usage.
Monitoring for therapeutic levels during amiodarone therapy.
Description.
Amiodarone is a fat-soluble, Class III antidysrhythmic, with several mechanisms of action, including (weak) negative inotropic activity coupled with compensatory vasodilatation, prolongation of cardiac tissue refractory period, depression of sinus node automaticity, and slowing of atrioventricular node conduction. It is used to treat clients with a history of life-threatening dysrhythmias that are not controllable by other drugs and after a myocardial infarction for symptomatic or sustained ventricular dysrhythmias. Because amiodarone is fat soluble, with a long half-life, it takes up to 4 weeks to reach steady-state levels and will remain in the fat-storage sites of the body long after it is discontinued. Amiodarone is metabolized and excreted primarily by the liver. This drug's potentially life-threatening side effects (acute hepatitis, pulmonary toxicity, bronchiolitis obliterans, pulmonary fibrosis) necessitate close monitoring of blood levels as well as clear and specific client teaching about side effects.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. MAY be drawn during hemodialysis.
Procedure
1. Draw the specimen before the dose, or at least 12 hours after the last dose.
2. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results may not be available for several days.
2. If activated charcoal was given for elevated levels, the client should drink 4-6 glasses of water each day for 2 days to prevent constipation. Activated charcoal will also cause stools to be black for a few days.
Factors That Affect Results
1. Height and weight have not been shown to affect plasma concentrations.
2. Amiodarone levels in stored specimens decrease over time. One study recommends the following correction factors for stored values:
Time Sample Stored Before Testing Correction Factor
24 hours Add 8% to obtained value
48 hours Add 16% to obtained value
72 hours Add 19% to obtained value
7 days Add 23% to obtained value
14 days Add 32% to obtained value View full size
Other Data
1. Amiodarone minor side effects include (usually reversible) corneal and skin micro deposits of the drug, causing grayish coloring of the sclera and skin, photosensitivity, and neuromuscular weakness. Side effects may take several months to appear.
2. Any concurrent digoxin dose should be reduced during amiodarone therapy.
3. Increases in serum creatinine may be related to the drug itself.
Amitriptyline
See Tricyclic Antidepressants—Plasma or Serum .
Ammonia (NH 3 )— Blood and Urine
Norm.
Norms vary by specific laboratory.
SI Units
Plasma
Adult 9.5-49 µg/dL 7-35 µmol/L
Newborn 90-150 µg/dL 64-107 µmol/L
First 2 weeks 79-129 µg/dL 56-92 µmol/L
Child 40-80 µg/dL 28-57 µmol/L
Urine
Spot 36-750 µg/dL 20-500 µmol/L
24-hour
Adult 140-1500 mg/N/24 hours 10-107 mmol/N/24 hours
Infant 560-2900 mg/N/24 hours 40-207 mmol/N/24 hours View full size
Arterial Blood in Uremic Clients
Adult before hemodialysis 98.32 mg/dL
Adult after hemodialysis 63.18 mg/dL View full size
Venous Blood in Uremic Clients
Adult before hemodialysis 71.70 mg/dL
Adult after hemodialysis 58.05 mg/dL View full size
Hepatic Encephalopathy Symptoms and Treatment
Symptoms.
(Symptoms do not correlate well with blood levels.) Asterixis, ataxia, coma, confusion, drowsiness, seizures, sluggish speech, somnolence, stupor.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Administer lactulose nasogastrically or rectally.
2. Both hemodialysis and peritoneal dialysis WILL remove NH 3 .
Increased.
Alzheimer's disease, azotemia, carbamoyl phosphate synthetase I deficiency (CPSID), cirrhosis, coma (diabetic, hepatic), congestive heart failure, erythroblastosis fetalis, esophageal varices (hemorrhagic), exercise, hepatic encephalopathy, hepatitis (acute), pneumonia, portacaval shunt, premature infant (with neurologic abnormalities), Reye's syndrome, and shock. Drugs include acetazolamide, ammonium salts, asparaginase, chlorothiazide, heparin calcium, heparin sodium, methicillin sodium, neomycin, thiazide diuretics, urea, and valproic acid.
Decreased.
Hypertension (essential, malignant) and renal failure.
Description.
Ammonia is a waste product from nitrogen breakdown during protein metabolism. It is metabolized by the liver and excreted by the kidneys as urea. Elevated levels caused by hepatic dysfunction may lead to encephalopathy.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Refrigerated gray topped, lavender topped, or heparinized green topped.
2. Do NOT draw during hemodialysis.
3. See Client and Family Teaching .
4. Notify laboratory personnel that a blood sample for ammonia level will be arriving.
Procedure
Samples should preferably be taken from arterial or earlobe capillary blood because ammonia metabolism in muscle causes increased levels in venous blood.
1. Arterial sampling : Draw a 4-mL blood specimen.
2. Capillary sampling : Using a lancet, completely fill a capillary tube with blood from the earlobe.
3. Venous sampling : Leaving a tourniquet in place no more than 15 seconds, draw a 4-mL blood specimen. If a syringe is used for blood collection, uncap the tube and transfer the blood into it without using the needle. Tilt the tube back and forth to mix the contents.
Postprocedure Care
1. Place the specimen in an ice-water bath.
2. Transport the specimen to the laboratory immediately.
Client and Family Teaching
1. Fast, except for water, and refrain from smoking for 8-10 hours before sampling.
2. Avoid stress and strenuous exercise for several hours before sampling.
Factors That Affect Results
1. Green topped tubes containing ammonium-heparin should not be used.
2. Reject hemolyzed specimens.
3. A delay in processing the specimen may cause falsely elevated results.
4. A high-protein diet may increase levels.
Other Data
1. Ammonia levels are NOT reliable indicators of impending hepatic coma.
2. Liver transplant corrects hyperammonemia.
Amniocentesis and Amniotic Fluid Analysis— Diagnostic Routine Analysis
Color: Colorless, straw-colored, or clear to milky-colored.
SI Units
Acetylcholinesterase Negative
Alpha-fetoprotein:
12 weeks of gestation ≤ 42 µg/mL
14 weeks of gestation ≤ 35 µg/mL
16 weeks of gestation ≤ 29 µg/mL
18 weeks of gestation ≤ 20 µg/mL
20 weeks of gestation ≤ 18 µg/mL
22 weeks of gestation ≤ 14 µg/mL
30 weeks of gestation ≤ 3 µg/mL
35 weeks of gestation ≤ 2 µg/mL
40 weeks of gestation ≤ 1 µg/mL
(Normal values may also be reported in multiples of the median [MOM] or 0.5-3.0 MOM.)
Bilirubin
Trimesters 1 and 2 ≤ 0.074 mg/dL ≤ 1.2 µmol/L
40 weeks of gestation ≤ 0.024 mg/dL ≤ 0.4 µmol/L
Calcium 4 mEq/L 4 mmol/L
Carbon dioxide 16 mEq/L 16 mmol/L
Chloride 102 mEq/L 102 mmol/L
Creatinine
≤ 27 weeks of gestation 0.8-1.1 mg/dL 71-97 µmol/L
30-34 weeks of gestation 1.1-1.8 mg/dL 97-159 µmol/L
35-40 weeks of gestation 1.8-4.0 mg/dL 159-354 µmol/L
Estriol
Trimesters 1 and 2 ≤ 9 µg/dL ≤ 309 nmol/L
Term <59 dl="" g="" span="" style="white-space: pre;"> <2023 nmol="" p="">Glucose 30 mg/dL 2 mmol/L
Lecithin
<35 gestation="" of="" span="" style="white-space: pre;" weeks=""> 6-9 mg/dL ≥35 weeks of gestation 15-20 mg/dL
Lecithin/sphingomyelin (L/S) ratio
Immaturity ≤ 1 : 1 <1 1="" :="" p="">Borderline maturity 1 : 1-2 : 1 1 : 1-2 : 1
Maturity >2 : 1 >2 : 1
After maturity ≥4 : 1 ≥4 : 1
Meconium Negative
Osmolality Equals serum osmolality
pCO 2
Trimesters 1 and 2 33-55 mm Hg 4.4-7.3 kPa
Term 42-55 mm Hg 5.6-7.3 kPa
pH
Trimesters 1 and 2 7.12-7.38 7.12-7.38
Term 6.91-7.43 6.91-7.43
Potassium 4.9 mEq/L 4.9 mmol/L
Protein, total
Trimesters 1 and 2 0.36-0.84 g/dL 0.36-0.84 g/dL
Term 0.07-0.45 g/dL 0.07-0.45 g/dL
Sodium 7-10 mEq/L lower than serum sodium 7-10 mmol/L lower than serum sodium
Sphingomyelin 4-6 mg/dL
Total protein 2.5 g/dL 25 g/L
Urea
Trimesters 1 and 2 12-24 mg/dL 1.2-4 mmol/L
Term 19-42 mg/dL 3.2-7 mmol/L
Uric acid
Trimesters 1 and 2 2.76-4.68 mg/dL 0.17-0.28 mmol/L
Term 7.67-12.13 mg/dL 0.46-0.72 mmol/L View full size
Abnormalities That May Be Found on Routine Analysis
Abnormal Color Possible Cause
Yellow Caused by fetal bilirubin, erythroblastosis fetalis
Green Caused by meconium, breech presentation, fetal death, defecation, distress, hypoxia, intrauterine growth restriction, status post
Red Caused by presence of blood, intrauterine hemorrhage maturity, vagal stimulation
Port wine Acute fetal distress, abruptio placentae
Brown Oxidized hemoglobin, maternal tissue trauma, fetal death, fetal maceration View full size
SI Units
Abnormal Bilirubin
Fetal involvement 0.10-0.28 mg/dL = 1+ 1.6-4.5 µmol/L
Later fetal involvement 0.29-0.36 mg/dL = 2 + 4.7-5.8 µmol/L
Fetal distress 0.47-0.95 mg/dL = 3 + 7.6-15.4 µmol/L
Fetal death >0.95 mg/dL = 4 + >15.4 µmol/L View full size
Abnormal Creatinine
35-40 weeks of gestation
Large muscle mass, possible diabetes >4 mg/dL >354 µmol/L
Low birth weight <2 dl="" mg="" span="" style="white-space: pre;">
<177 full="" mol="" nbsp="" p="" size="" view="">Increased Alpha-fetoprotein.
Anencephaly, cleft lip and palate, cystic fibrosis, duodenal atresia, esophageal atresia, fetal bladder neck obstruction with hydronephrosis, fetal death, meningomyelocele, multiple pregnancy, nephrosis (congenital), neural tube defects, spina bifida, omphalocele, and Turner's syndrome.
Increased Bilirubin.
Anencephaly, erythroblastosis fetalis, hemolytic disease of the newborn, hydrops fetalis, intestinal obstruction, and Rh sensitization.
Increased Lamellar Bodies in Amniotic Fluid.
Respiratory distress syndrome.
Positive Acetylcholinesterase.
Neural tube abnormalities that allow cerebrospinal fluid (which contains acetylcholinesterase) to leak into the amniotic sac.
Positive Meconium.
Fetal distress.
Decreased Alpha-fetoprotein.
Not applicable.
Decreased Bilirubin.
Not clinically significant.
Decreased Creatinine.
Fetal lung immaturity.
Chromosome Analysis.
Interpretation required.
Description.
Detection of fetal jeopardy or genetic disease and determination of fetal maturity. Amniocentesis is a 20- to 30-minute procedure in which an aspiration of amniotic fluid is taken transabdominally and is usually performed after week 12 of gestation. In routine analysis, amniotic fluid is examined for levels of calcium, chloride, carbon dioxide, creatinine, estriol, glucose, pH, potassium, sodium, protein, urea, uric acid, and culture and for genetic defects, chromosomal studies, detection of fetal jeopardy or distress (by color, bilirubin), and to measure lung maturity (by L/S ratio) and age (by creatinine of the fetus). Alpha 1 -fetoprotein is a globulin protein secreted by the yolk sac and by fetal liver cells during hepatic cell multiplication. The highest amounts are found during pregnancy and in hepatic cancer. Measurement is usually performed from week 16 to 20 to help identify fetal neural abnormalities, gastroesophageal atresia, and nephrosis. Chromosome analysis of amniotic fluid cells is performed by examination of karyotyped cells for genetic abnormalities such as Down syndrome, Tay-Sachs disease, and other inborn errors of metabolism. Amniotic fluid is examined for color and bilirubin level for detection of fetal jeopardy or distress caused by hemolysis of fetal red blood cells. Erythroblastosis fetalis occurs when maternal antibodies attack fetal red blood cells, causing fetal anemia. This occurs when the mother's blood contains the Rh factor that reacts with fetal erythrocyte antigens. The test is usually performed at gestation week 24 or later and can help determine the need for intrauterine fetal blood transfusion. After the 35th week of pregnancy, the phospholipid levels of lecithin and sphingomyelin change in a predictable pattern that indicates the level of maturity of fetal lungs. Lecithin rises and sphingomyelin decreases as the fetal lungs mature.
Professional Considerations
Informed consent is recommended for genetic testing and for the procedure itself.
Risks
Bleeding, intrauterine death, premature labor, spontaneous abortion.
Contraindications
Abruptio placentae, incompetent cervix, placenta previa, and a history of premature labor.
Preparation
1. Obtain an amniocentesis tray, surgical scrub solution, a light-protected container, and povidone-iodine solution. Also obtain RhoGAM for Rh-negative mothers.
2. Obtain maternal vital signs. Auscultate baseline fetal heart tones.
3. Note the estimated date of conception and week of gestation on the laboratory requisition.
4. Procedure should be performed in a darkened room if the specimen will be tested for bilirubin.
5. See Client and Family Teaching .
6. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
Procedure
1. The position of the fetus and a pocket of amniotic fluid are determined using ultrasound and palpation, with the mother in a supine position.
2. The mother's abdominal area is cleansed with surgical scrub solution and povidone-iodine and allowed to dry.
3. The aspiration site is draped to demarcate a sterile field.
4. The mother is instructed to place her hands behind her head, and the aspiration site is anesthetized with 1 mL of 1% or 2% lidocaine intradermally and subcutaneously.
5. A 20- to 22-gauge, 5-inch-long spinal needle with a stylet is inserted through the abdominal wall into the intrauterine cavity, and the stylet is withdrawn.
6. About 7-15 mL of amniotic fluid is aspirated through the spinal needle into a syringe, and the needle is withdrawn. Use a 20-mL amniotic fluid sample for direct genetic analysis for the four most common mutations responsible for Tay-Sachs disease.
Postprocedure Care
1. Apply a dry, sterile dressing to the aspiration site.
2. Inject 2-5 mL of amniotic fluid into a light-protected (foil-covered or amber) test tube to test for bilirubin. Inject 5-10 mL of amniotic fluid into a sterile, siliconized glass container or a polystyrene container for culture and genetic and other studies (AFP). Specimens to be transported to another site for testing should be packed in a cool, insulated container to maintain a temperature of 2-5 degrees C. Freezing temperatures should be avoided.
3. Obtain the mother's vital signs. Auscultate fetal heart tones for changes from the baseline value.
4. The mother should rest on her right side for 15-20 minutes after the procedure.
5. RhoGAM may be prescribed for Rh-negative mothers.
6. Transport the amniotic fluid specimen to the laboratory immediately and refrigerate.
Client and Family Teaching
1. Empty your bladder immediately before the procedure if gestation is 21 weeks or more. You must have a full bladder during the procedure if gestation is 20 weeks or less.
2. It is important to lie motionless throughout the procedure. You may experience a strong contraction with the needle insertion.
3. Chromosome analysis results may take up to 4 weeks.
4. After the procedure, notify the physician for cramping, abdominal pain, unusual vaginal drainage/fluid loss, fever, chills, dizziness, or more or less than the usual amount of fetal activity.
5. Inform the client with abnormal genetic findings of choices regarding pregnancy and pregnancy termination. Also refer the client for genetic counseling before future attempts to become pregnant. Refer to section in this book on “Informed Consent for Genetic Testing”.
Factors That Affect Results
1. Reject frozen or clotted specimens.
2. Inadvertent aspiration of maternal urine can be ruled out by testing the specimen for blood urea nitrogen (BUN) and creatinine. Urine BUN is >100 mg/dL, whereas amniotic fluid is well under 100 mg/dL. Urine creatinine is usually >80 mg/dL, whereas amniotic fluid creatinine is usually ≤ 4 mg/dL.
3. Nonsiliconized glass containers for routine analysis may result in cell adherence on the sides of the container.
4. Amniotic fluid testing must be performed within 3 days of collection.
5. Amniocentesis should be performed between weeks 24 and 28 when one is checking for hemolytic disease of the newborn and Rh sensitization.
6. Falsely low bilirubin levels may result from failure to protect the specimen from light.
7. Specimens contaminated with blood should be tested for fetal hemoglobin to determine whether the blood is of maternal or fetal origin. Fetal blood contamination results in falsely high bilirubin levels. Fetal or maternal blood will interfere with measurements of fetal lung maturity and amniotic fluid constituents that are also constituents of plasma, such as protein, potassium, and glucose.
8. Creatinine levels are affected by maternal creatinine clearance and maternal creatinine levels. A concurrent maternal serum creatinine should be drawn. Maternal serum to amniotic fluid creatinine ratio should be about 2 : 1.
9. Elevated AFP results may be caused by contamination of the specimen with fetal blood.
10. Small and closed neural tube defects may not cause elevated AFP levels.
11. Accurate L/S ratio measurement is not possible if the specimen is contaminated with blood (fetal or maternal) or meconium.
Other Data
1. Direct karyotyping of placental villi samples obtained by needle aspiration has been found to yield faster results than amniotic fluid chromosome analysis. (See Chorionic villi sampling—Diagnostic .)
2. Chromosomal aberration has been found in 4.6% of fetuses in women >38 years of age, the most common being trisomy 21 (62%), Klinefelter's syndrome (11%), and Edward's syndrome (trisomy 18) (11%).
3. For diamniotic twin pregnancies, each amniotic sac should be sampled.
4. Early amniocentesis is feasible from 11 weeks of gestation and can be performed for the usual indications as an alternative to chorionic villus sampling. Results are available in less than 1 week using cytogenetic techniques.
5. Prenatal cystic fibrosis profile may be performed by polymerase chain reaction (PCR) for mutations (F508, R553X, g551D, g542X, n1303K, and w1282X).
6. Amniotic fluid neuron-specific enolase is useful as a marker for neonatal neurologic injury.
7. Genetic testing of cell free fetal DNA using real-time quantitative polymerase chain reaction is available and used as an alternative to amniocentesis in some countries. This test can identify fetal gender and some inherited disorders from a maternal blood sample. Disorders identified include disorders where a single gene is involved, and X-linked conditions. Findings are unreliable at less than 7 weeks gestation and have 94.8% sensitivity and 98.9% specificity at 7-12 weeks, and 95.5% sensitivity and 99.1% specificity at 13 through 20 weeks, and the most optimal results 99.0% specificity and 99.6% sensitivity after 20 weeks of gestation.
8. The Genetic Information Nondiscrimination Act of 2008 prohibits health plans from using genetic family history or genetic test results from influencing eligibility or premiums for health insurance. It also prohibits employers from using this information to influence decisions about hiring, terminating employment, or employment pay, promotions or privileges.
Amniotic Fluid, Alpha-Fetoprotein
See Amniocentesis and Amniotic Fluid Analysis—Diagnostic .
Amniotic Fluid, Chromosome Analysis
See Amniocentesis and Amniotic Fluid Analysis—Diagnostic .
Amniotic Fluid, Erythroblastosis Fetalis
See Amniocentesis and Amniotic Fluid Analysis—Diagnostic .
Amniotic Fluid Analysis
See Amniocentesis and Amniotic Fluid Analysis—Diagnostic .
Amoxapine
See Tricyclic Antidepressants—Plasma or Serum .
Amphetamines— Blood
Norm.
Negative
Drug ng/mL µg/mL mg/L SI Units, nmol/L
Amphetamine sulfate 20-120 0.02-0.12 150-900
Toxic level >200 >2 >1500
Chlorphentermine 100-400 0.10-0.40 750-3000
Diethylpropion 1-10 0.001-0.010 7.5-75
Ephedrine 50-100 0.05-0.10 375-750
Fenfluramine 30-300 0.03-0.30 225-2250
Methamphetamine 10-50 0.01-0.05 75-375
Toxic level >500 >5 >3750
p-Methoxyamphetamine <200 span="" style="white-space: pre;"> <0 .2="" span="" style="white-space: pre;"> <1500 p="">Methylenedioxyamphetamine <400 span="" style="white-space: pre;"> <0 .4="" span="" style="white-space: pre;"> <3000 p="">Toxic level >400 >4 >3000
Phendimetrazine 30-250 0.03-0.25 225-1875
Phenmetrazine 60-250 0.06-0.25 450-1875
Toxic level >400 >4 >3000
Phentermine 30-90 0.03-0.09 225-675
Phenylpropanolamine 50-100 0.05-0.10 375-750
Tranylcypromine 10-100 0.01-0.10 75-750 View full size
Toxic Levels Symptoms and Treatment
Symptoms.
Psychoses, tremors, convulsions, insomnia, tachycardia, dysrhythmias, impotence, cerebrovascular accident, and respiratory collapse.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Use gastric lavage or induce vomiting (with extreme caution) if within 4 hours of ingestion. (Induction of vomiting is contraindicated in clients with no gag reflex or with central nervous system depression or excitation.)
2. Give a slurry of activated charcoal 1 g/kg (minimum 30 g), followed by a magnesium citrate cathartic.
3. Amphetamine excretion may be accelerated by acidification of the urine with ammonium chloride 1-2 g intravenously or ascorbic acid 0.5-1.5 g orally every 4-6 hours to keep urine pH <5 .5.="" p="">4. Increase fluids to keep urine output at 3-6 mL/kg/hour.
5. Consider using mannitol or furosemide to force diuresis (efficacy of acid diuresis has not been clearly established).
6. Both hemodialysis and peritoneal dialysis WILL remove amphetamines.
7. Barbiturates may counteract amphetamine stimulant effects and chlorpromazine (Thorazine) may help control the symptoms of an overstimulated central nervous system.
Increased.
Stimulant drug abuse or use.
Description.
Amphetamines are sympathomimetic amines that act on the cortex and reticular activating system of the brain to stimulate the release and block the reabsorption of norepinephrine and dopamine. They cause mood elevation and wakefulness and decrease the perception of fatigue through stimulation of the heart and central nervous system. They are rapidly absorbed from the gastrointestinal tract and reach all tissues but concentrate in the central nervous system and are excreted by the kidneys. Half-lives vary depending on the individual drug. Synonyms include bennies, crystal, ice, pep pills, speed, uppers, and wake-ups. Side effects include multiple visceral aneurysms, cognitive deficits, hypertension, hyponatremia, jaw clenching, lack of appetite, loss of sexual interest, impaired gait, inability to concentrate, hepatic toxicity, memory problems, renal failure, and disseminated intravascular coagulation (DIC) (especially from MDMA/Ecstasy). Blood amphetamine levels are used for monitoring the appropriateness of dosage regimen and for detection of amphetamine abuse.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Lavender topped.
2. Assess for a history of drug abuse.
3. Do NOT draw during hemodialysis.
Procedure
1. Draw a 5-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 4 hours.
2. If activated charcoal was given for elevated levels, drink 4-6 glasses of water each day for 2 days to prevent constipation. Activated charcoal will also cause stools to be black for a few days.
3. Referrals to appropriate rehabilitation centers and therapeutic community programs should be offered to all addicted clients.
Factors That Affect Results
1. High concentrations of beta-phenethylamine, a blood product formed from the decomposition of protein, may mask a low amphetamine level.
Other Data
1. Toxicity in children occurs over a wide range of doses.
2. Abrupt discontinuation may cause psychotic symptoms.
3. See also Toxicology drug screen—Blood or urine .
Amsler Grid Test— Screen
Norm.
The lines are clearly visualized and appear straight. A black dot is visualized in the center of the grid. No distortions of the lines are seen. No spots are seen other than within each square.
Usage.
Detection of macular edema, macular blind spots, scotoma. A component of visual field testing for diagnosing glaucoma.
Description.
An optical screening test using a grid of intersecting lines with a black dot in the center. The visual acuity of the macular portion of the retina can be affected by macular edema, causing distortions of the lines, or by scotomas, causing blind spots, which make the grid appear to the client as having blank areas.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain an Amsler grid and an eye occluder (eye patch, hand held, or occluding eyeglasses).
Procedure
1. With one eye being covered, have the client view the Amsler grid at his or her usual reading distance.
2. Ask whether the black dot is visible, whether the complete square grid is visible when looking at the dot, whether the lines are perfectly straight, and whether any of the lines are blurred or look as though they are moving.
3. Ask if there are any blank areas on the grid, other than within each square. Have the client draw what he or she sees if the answer to any of the questions is yes.
4. Repeat the test for the other eye.
Postprocedure Care
1. Refer the client to a specialist if necessary.
Client and Family Teaching
1. The test takes less than 30 minutes.
Factors That Affect Results
1. Performing this test before retinal examination with an ophthalmoscope and fundus examination or refraction test avoids falsely abnormal results caused by retinal bleaching from the bright light or loss of focusing ability.
Other Data
1. An abnormal test indicates the need for more specific testing such as fluorescein angiography.
2. Amsler grid reports have poor validity and cannot be accurately interpreted for use in the clinical diagnosis of retinal defects or overall ocular disease.
Amylase— Serum and Urine and Amylase Clearance
Norm.
Serum Amylase SI Units
Adults
18-70 years 30-110 30-110 U/L U/L
>70 years 20-160 U/L 20-160 U/L
Children
0-3 months 0-30 U/L 0-30 U/L
3-6 months 7-40 U/L 7-40 U/L
7-8 months 7-57 U/L 7-57 U/L
9-11 months 11-70 U/L 11-70 U/L
12-17 months 11-79U/L 11-79 U/L
18-35 months 19-92 U/L 19-92 U/L
3-4 years 26-106 U/L 26-106 U/L
5-12 years 30-119 U/L 30-119 U/L
13-18 years 30-110 U/L 30-110 U/L View full size
Urine Amylase
Mayo Clinic method 10-80 amylase U/hour
Somogyi method 26-950 U/24 hours
Beckman method 1-17 U/hour
Amylase clearance 1%-4%
Macroamylasemia Decreased (usually <1 clearance="" normal="" or="" p="">Pancreatitis Increased clearance View full size
Increased.
Abdominal aortic aneurysm (ruptured), acute exacerbation of chronic pancreatitis, ampulla of Vater obstruction, cerebral trauma, cholecystitis (acute), choledocholithiasis, common bile duct obstruction, diabetic ketoacidosis, eating disorders (vomiting, pancreatitis), ectopic pregnancy, empyema (gallbladder), fructose malabsorption, hyperthyroidism, intestinal obstruction with strangulation, intra-abdominal abscess, lung cancer, macroamylasemia, mesenteric thrombosis, mumps, pancreatic duct obstruction, pancreatic cancer, pancreatitis (acute), perforated intestine, perforated ulcer, peritonitis, salivary gland disease (acute, duct obstruction, suppurative inflammation), spasm of sphincter of Oddi, surgery (postoperative upper abdominal, peripancreatic), trauma (pancreas, spleen), tuberculosis. Drugs include aspirin, opiates, propofol, radiographic dyes, and thiazides. Herbs or natural remedies include vinho abafado (augmented Port wine, Brazil).
Decreased.
Alcoholic liver disease, alcoholism, burns (severe), cachexia, cirrhosis, cystic fibrosis (advanced), hepatic abscess, hepatic cancer, hepatitis, pancreatic cancer, pancreatitis (acute fulminant, advanced chronic), poisoning, renal dysfunction, thyrotoxicosis (severe), and toxemia of pregnancy. Drugs include glucose and fluorides.
Description.
An enzyme produced by the pancreas and salivary glands that aids digestion of complex carbohydrates. It is excreted by the kidneys. In acute pancreatitis, serum amylase levels start rising at about 2 hours after the onset, peak at about 24 hours, and return to normal in 2-4 days after the onset. Urine amylase levels will be elevated from several hours after the onset until 7-10 days after the onset. Because urine amylase levels remain elevated longer than serum amylase levels, they are useful for providing evidence of pancreatitis after serum amylase has returned to normal levels.
Amylase clearance is reported as a ratio in proportion to creatinine clearance. This amylase clearance/creatinine clearance ratio helps determine whether hypermacroamylasemia is secondary to pancreatitis (see Norms):
Amylase clearance=(urine amylase concentration)×(serum creatinine concentration)/(serum amylase concentration)×(urine creatinine concentration)
Amylase concentration rises and falls in tandem with lipase concentration in acute pancreatitis but is a less specific marker than lipase for this condition.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a urine container without preservatives, including toluene or acetic acid preservatives, in sizes as follows: 1-L size, 2- or 6-hour collection; 2-L size, 8- or 12-hour collection; 3-L size, 24-hour collection.
2. Tube: Red topped, red/gray topped, or gold topped.
3. List medications taken in the past 24 hours on the laboratory requisition.
4. Screen client for the use of herbal preparations or natural remedies such as vinho abafado.
Procedure
1. Discard the first morning-voided urine specimen.
2. Collect a timed urine specimen over 2, 6, 8, 12, or 24 hours in a refrigerated or iced container without preservatives or to which toluene or acetic acid has been added. For catheterized clients, keep the drainage bag on ice and empty the urine into the collection container hourly.
3. Encourage fluid intake throughout the collection period if not contraindicated.
4. For serum collection, draw a 4-mL sample at least 2 hours after a meal and before treatment has begun.
Postprocedure Care
1. Check pH of specimen. If pH is <6 2="" 5="" add="" and="" container="" mix="" ml="" naoh="" of="" p="" the="" to="" well.="">2. Send a well-mixed 10-mL aliquot to the laboratory and refrigerate.
3. List the beginning and ending times of urine specimen collection on the laboratory requisition, as well as total volume of the 24-hour specimen.
Client and Family Teaching
1. For the urine test, save all urine voided in the 2-, 6-, 8-, 12-, or 24-hour period. Urinate before defecating to avoid loss of urine and to avoid contaminating the specimen with feces or toilet tissue. If any urine is accidentally discarded, discard the entire specimen and restart the collection the next day.
2. Do not drink alcohol for 24 hours before sampling.
Factors That Affect Results
1. Urine amylase determinations should not be performed on females during menstruation.
2. Results reported in U/mL give an inaccurate picture because they are influenced by the varying urine volumes, depending on the length of the collection period.
3. Reject hemolyzed specimens.
4. Drugs that may falsely elevate results of serum amylase include aminosalicylic acid, asparaginase, azathioprine, bethanechol, bethanechol chloride, chloride salts, cholinergics, corticosteroids, corticotropin, cyproheptadine hydrochloride, ethacrynic acid, ethyl alcohol (large quantities), fluoride salts, furosemide, indomethacin, loop diuretics, mercaptopurine, methacholine, narcotic analgesics, oral contraceptives, pancreozymin, rifampin, sulfasalazine, and thiazide diuretics.
5. Falsely decreased results of serum amylase may be caused by citrates and oxalates.
6. pH of sample of <6 30="" a="" cause="" decreased="" may="" p="" result.="" to="" up="">7. Massive hemorrhagic pancreatic necrosis may cause so much pancreatic cell destruction that amylase cannot be produced, resulting in no elevation in serum amylase.
8. Contamination of the serum specimen with saliva will cause falsely elevated results.
9. Serum lipemia (hyperlipidemia) or hypertriglyceridemia may result in falsely low or spuriously normal serum amylase results.
10. Results are invalidated if the specimen is drawn less than 72 hours after cholecystography with radiopaque dyes.
11. Falsely high serum amylase results may be caused by renal failure.
12. There can be pronounced fluctuation in serum amylase levels, ranging from 115% to 1160% in clients with macroamylasemia, and this fluctuation may cause confusion in differentiating macroamylasemia from other causes of hyperamylasemia.
13. Baseline levels increase during pregnancy.
Other Data
1. Macroamylasemia causes a high serum but normal urine amylase concentration.
2. Urine amylase does not produce falsely high results with renal failure as serum amylase does.
3. Normal serum amylase may occur in pancreatitis, especially chronic pancreatitis and severe necrotizing pancreatitis.
ANA
See Antinuclear Antibody—Serum .
Anaerobic Culture
See Body Fluid—Anaerobic Culture .
ANCA
See Antineutrophil Cytoplasmic Antibody Screen—Serum .
Androstenedione— Serum
Norm.
SI Units
Adult female 85-275 ng/dL 3.0-9.6 nmol/L
Postmenopausal 30-140 ng/dL 1.0-4.8 nmol/L
Adult male 70-205 ng/dL 2.6-7.2 nmol/L
Cord blood 30-150 ng/dL 1.0-5.2 nmol/L
Premature newborn 80-446 ng/dL 2.8-15.6 nmol/L
Newborn 20-290 ng/dL 0.7-10.1 nmol/L
Female Children
1-3 months 15-25 ng/dL 0.5-0.9 nmol/L
3-5 months 10-15 ng/dL 0.3-0.5 nmol/L
Male Children
1-3 months 20-45 ng/dL 0.7-1.6 nmol/L
3-5 months 10-40 ng/dL 0.3-1.4 nmol/L
Panic level (all ages) >1000 ng/dL >34.9 nmol/L View full size
Usage.
Nonspecific evaluation of androgen production in female hirsutism.
Increased.
Alzheimer's disease, congenital adrenal hyperplasia, Cushing's syndrome, hirsutism, recurrent miscarriages, Stein-Leventhal disease (polycystic ovarian syndrome), and tumor (adrenal, ovarian). Herbs or natural remedies include Siberian ginseng.
Decreased.
Decreases with age in men and potential factor in pathogenesis of bone loss.
Description.
A metabolite of dehydroepiandrosterone sulfate (DHEA-S) produced in the ovaries and the adrenal gland that is converted to testosterone in peripheral tissues. Peak levels occur in the early morning and low levels in the late afternoon. After puberty, levels rise and peak around 20 years of age. Elevation is one of several causes of female hirsutism, which is characterized by a male hair-growth pattern. Very elevated levels are suggestive of the presence of a virilizing tumor.
Professional Considerations
Consent form NOT required.
Preparation
1. Schedule the test at least 7 days before or after a female client's menstruation.
2. Tube: Red topped, red/gray topped, or gold topped.
3. Screen client for the use of herbal preparations or natural remedies, such as Siberian ginseng.
4. See Client and Family Teaching .
Procedure
1. Draw a 2-mL blood sample. Draw between 0600 and 0900 for peak levels.
Postprocedure Care
1. Place the specimen on ice.
2. Transport the specimen to the laboratory immediately for spinning and freezing of serum.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Test must be drawn 1 week before or after menstruation to avoid falsely elevated values.
Factors That Affect Results
1. Results are invalidated if the client has undergone a scan involving radioactive dyes within 1 week before specimen collection.
Other Data
1. Plasma levels do not correlate well with the severity of symptoms.
Angel Dust
See Phencyclidine, Qualitative—Urine .
Angiocardiography Procedure
See Cardiac Catheterization—Diagnostic .
Angiogram (Angiography)
See Arteriogram—Diagnostic ; Cardiac Catheterization—Diagnostic ; Cerebral Angiogram—Diagnostic ; Pulmonary Angiogram—Diagnostic ; or Renal Angiogram—Diagnostic .
Angiography
See Cerebral Angiogram—Diagnostic .
Angiotensin-Converting Enzyme (ACE)— Blood
Norm.
SI Units
Adults 9-67 U/L 153-1139 µKat/L
Children
0-6 years 18-90 U/L 306-1530 µKat/L
7-14 years 24-121 U/L 408-2057 µKat/L
15-17 years 18-101 U/L 306-1717 µKat/L View full size
Increased.
Arthritis (rheumatoid), bronchitis, cervical adenitis, cirrhosis (nonalcoholic), connective tissue disease, fungal diseases, Gaucher disease, histoplasmosis, Hodgkin's disease, hypercalcemia, hyperthyroidism (untreated), Langerhans cell histiocytosis, leprosy, myeloma, non-Hodgkin's lymphoma, pulmonary embolus, pulmonary fibrosis, sarcoidosis (active), and scleroderma.
Decreased.
Acute respiratory distress syndrome, coccidioidomycosis, diabetes mellitus, farmer's lung, hypothyroidism, pulmonary neoplasm (advanced), severe illness, and tuberculosis. Drugs include cadmium, captopril, estrogen (replacement therapy), l -arginine, and steroids.
Description.
An enzyme found mainly in lung epithelial cells and in smaller amounts in blood vessels and renal tissue that converts angiotensin I to angiotensin II—a vasopressor that also stimulates the adrenal cortex to produce aldosterone. High levels of ACE are strongly correlated with pulmonary sarcoidosis and levels drop to normal when spontaneous remission occurs.
Professional Considerations
Consent form NOT required.
Preparation
1. Write the client's age on the laboratory requisition.
2. Tube: Red topped, red/gray topped, gold topped, or green topped.
3. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory immediately. Freeze the specimen and store it in dry ice if the test is not performed immediately.
Client and Family Teaching
1. Fast for 12 hours before sampling.
Factors That Affect Results
1. Reject hemolyzed or lipemic specimens.
2. A delay in testing or failure to freeze the specimen if not tested immediately may cause falsely low results.
3. In clients with sarcoidosis, levels may be normal if clients have been treated with corticosteroids.
Other Data
1. ACE is useful in evaluating the effectiveness of therapy and in confirming clinical status.
ANH
See Natriuretic Peptides—Plasma .
Animals and Rabies
See Fluorescent Rabies Antibody—Specimen .
Animals and Rabies Negri Bodies, Brain Tissue— Specimen
Norm.
Negative.
Positive.
Rabies.
Description.
A postmortem histologic examination of the brain tissue of an animal suspected to have rabies, usually performed after the animal has bitten a human. Rabies produces Negri bodies, a specific and diagnostic lesion of the central nervous system that contains inclusion bodies in the cytoplasm of the nerve cells. Animal specimen examination is the only method to identify rabies because there is no laboratory or diagnostic test to identify the disease in humans until after symptoms appear (listed below). Diagnosis in humans is based on history and symptoms. Symptoms may appear 10 days to a year after the bite but more commonly appear in humans 2-8 weeks later.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a container and ice or dry ice.
2. Prepare for the examination by wearing protective clothing, a face shield, and heavy rubber gloves.
Procedure
1. The animal is killed and decapitated. The head is sealed in a watertight metal container and refrigerated as follows: with regular ice if the specimen will be examined within 24 hours; with dry ice if the specimen will be examined after 24 hours.
2. Thin-tissue impressions are made from the medulla, the cerebellum, and Ammon's horn of the hippocampus; immersed for 5 seconds in Seller's stain and then in tap water; and examined under high magnification. Negri bodies appear as cherry red, sharply defined, spherical, oval, or elongated bodies containing dark blue staining granules.
Postprocedure Care
1. Include a detailed history of the date of human exposure, the method of exposure, the names and addresses of the client(s) exposed, the animal's owners, the species and breed of animal, whether it died or was killed, and its vaccination history, if known.
2. The bitten human should be monitored for the development of signs of rabies, which include laryngeal spasm when drinking water, restless behavior, hyperreactivity or convulsions with increased sensory input, neuromuscular twitching, tachypnea/hyperventilation, hydrophobia, and excess salivation.
Client and Family Teaching
1. Client and family should observe for signs of rabies (listed above) for the next 12 months. Notify the physician immediately if symptoms appear.
2. Have pets vaccinated against rabies.
3. If a bite occurs, clean the wound quickly with a disinfectant to kill any rabies virus in the wound.
4. The family should follow universal precautions in handling any items from the client that have been contaminated with saliva until a year has passed without symptoms.
Factors That Affect Results
1. Inability to obtain animal or brain tissue.
Other Data
1. The likelihood of Negri body development increases with the length of time the animal lives after acquiring rabies. Therefore Negri bodies may not always be present.
2. Results should be confirmed by mouse inoculation intracerebrally with the animal's brain tissue.
3. The only method of preventing rabies is animal vaccination.
4. Rabies is a reportable disease in most areas, as are animal bites.
Anion Gap— Blood
Norm.
SI Units
With K + in the equation 12-20 mEq/L 12-20 mmol/L
Without K + in the equation
Adults 8-16 mEq/L 8-16 mmol/L
Child < age 3 10-14 mEq/L 10-14 mmol/L
Child ≥ age 3 10-18 mEq/L 10-18 mmol/L
Norm using Beckman E4A or CX5 analyzer 3-11 mEq/L 3-11 mmol/L View full size
Increased.
Acidosis, cancer, carbon monoxide poisoning, chronic renal failure, cyanide poisoning, dehydration, ethyl alcohol ketoacidosis, ethylene glycol poisoning, heart disease, heatstroke, hypertension, hypocalcemia, hypomagnesemia, lactic acidosis, metabolic acidosis caused by diabetic ketoacidosis (because of acetone, beta-hydroxybutyrate ketone content), methanol poisoning, multiple acyl-CoA dehydrogenase deficiency, renal failure, salicylate overdose, and uremia. Drugs include acetaminophen (alone or in combination with oxycodone), acetazolamide, ammonium chloride, antihypertensives, carbenicillin, corticosteroids, 5% dextrose in water (prolonged infusion), diazoxide, dimercaprol, ethacrynic acid, ethyl alcohol (ethanol), ethylene glycol, formaldehyde, fructose, furosemide, hippuric acid, hydrogen sulfide, iodine, iron, isoniazid, metformin, methenamine mandelate, nalidixic acid, nitrates, nitrites, oral phospho soda, oxalic acid, paraldehyde, penicillins, phenformin, propofol (infusion 100 µg/kg/min), salbutamol, salicylates, sodium bicarbonate, sodium nitroprusside, sorbitol, streptozotocin, sulfur (elemental), thiazides, ticarcillin, toluene, xylitol, and any drug that may result in hypotension with reduced tissue perfusion or renal failure.
Decreased.
Bromism (from cough medications, very low to negative anion gap caused by halide ion falsely measured as chloride), hyperdilution, hypercalcemia, hypermagnesemia, hypoalbuminemia (causes a decrease in amount of anions not measured) (1 g/dL drop in serum albumin correlation with a 2.5 mEq/L decrease in anion gap), hyponatremia, hypophosphatemia, ingestion (of salicylate, ethanol, ethylene glycol, formaldehyde/methanol, paraldehyde, toluene, or sulfur), multiple myeloma (causes abnormal cations called paraproteins), polyclonal gammopathy, proteinuric hypertension from pregnancy, Waldenström's macroglobulinemia. Drugs include alkalis, ammonium chloride, boric acid, bromides, chlorpropamide, cholestyramine, corticotropin, cortisone acetate, hypercalcemia, hyperkalemia, hypermagnesemia, lithium carbonate (toxicity) (causes very low to negative anion gap because of excess unmeasured cation), magnesium-containing antacids, oxyphenbutazone, phenylbutazone, polymyxin B, sodium chloride (large amounts intravenously), tromethamine, and vasopressin. Herbal or natural remedies include licorice.
Description.
A calculation of the difference between the major cations and the major anions in the blood that helps determine the cause of metabolic acidosis. The two formulas used to determine the anion gap are:
Anion gap=([Na+])−([Cl−]+[HCO−])orAnion gap=([Na+]+[K+])−([Cl−]+[HCO−])
Anion gap is simply a term used to signify the amount of unmeasured anions in the blood plasma. The anion “gap” is created on paper because the formula excludes some anions (such as proteins, organic acids, phosphates, sulfates, and cations) (such as calcium and magnesium and, sometimes, potassium). If all possible types of anions and cations were used in the formula, instead of only those above, the answer would be zero, because the body's homeostatic mechanisms ensure electrochemical balance in the plasma. The formula's result has different implications depending on whether the answer is positive or negative. A negative anion gap is less common than an elevated anion gap.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Do NOT draw during hemodialysis.
Procedure
1. Draw a 10-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Not applicable.
Factors That Affect Results
1. Metabolic acidosis may exist with a normal anion gap, as when bicarbonate is lost in body fluids and chloride is retained in the following conditions: hyperchloremic acidosis, renal tubular acidosis, biliary or pancreatic fistulas, and ileal loop hypofunctioning.
2. Iodine absorption from wounds packed with povidone-iodine solution may cause falsely low results.
3. Reject hemolyzed specimens.
Other Data
1. Normal anion gap can occur with diarrhea, hyperalimentation, ketoacidosis, renal tubular acidosis, ureterostomies, ingestion of ammonium chloride or ethanol, or infusion of total parenteral nutrition.
2. Treatment for an anion gap acidosis is to correct the cause. Sodium bicarbonate 1-2 mEq/kg has been used in some cases.
3. See also Ketone bodies—Blood ; Beta-hydroxybutyrate—Blood .
Ankle-Brachial Index (ABI)— Diagnostic
Norm.
Pressure Index Interpretation
≥0.86 Normal
0.75-0.85 Mild occlusive disease
0.50-0.75 Intermittent claudication
0.30-0.50 Severe disease: rest pain may occur; pregangrenous state
0.20-0.30 Poor probability for tissue healing or limb viability unless compensation by collateral blood flow occurs
<0 .20="" span="" style="white-space: pre;"> Ischemic or gangrenous extremities View full sizeUsage.
Assessment of arterial blood flow in clients with peripheral vascular disease; monitoring postoperative flow in the lower extremities after vascular surgery such as femoral bypass or after aortofemoral bypass from iliac occlusion; assessment of severity of peripheral vascular disease; predicting carotid artery stenosis. Cilostazol (Pletal) increases ABI at rest.
Description.
The ABI is a mathematically calculated ratio of the systolic pressure at a pulse point in a lower extremity with peripheral vascular disease as compared to the systolic pressure of the brachial artery. The index provides a quick, noninvasive assessment of how much arterial blood is perfusing the extremity. Typically an ABI that increases by at least 0.15 (15%) after vascular surgery indicates that the surgery was successful. A baseline in women with an ABI of <0 .60="" a="" as="" developing="" disability="" for="" higher="" indicates="" mile="" of="" outcomes="" p="" probability="" quarter="" severe="" significantly="" specific="" such="" walking="">
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain a dual-frequency Doppler ultrasonograph, a marker, two sphygmomanometers, and ultrasonic gel.
Procedure
1. Client is positioned supine.
2. The femoral, popliteal, dorsalis pedis, and posterior tibial pulse points in both lower extremities are palpated and identified with a marker.
3. The sphygmomanometer cuff is placed proximally to the marked site. If the flow is being assessed at the knee, the cuff is placed proximally to the popliteal pulse. If the flow is being assessed at the ankle, the cuff is placed proximally to the ankle.
4. Ultrasonic gel is placed over the marked site (popliteal, posterior tibial, or dorsalis pedis), and the Doppler flow signal is identified.
5. With the Doppler in place, the sphygmomanometer cuff is inflated until the Doppler flow signal disappears.
6. The cuff is slowly deflated, and the pressure at which the Doppler tone is again audible is noted and recorded.
7. The brachial systolic blood pressure in both arms is measured with a Doppler scanner, and the highest pressure is selected for use in the ABI calculation.
8. The ABI ratio is calculated with the following equation:
ABI ratio=[Lower extremity pressure from step 6]/[Brachial Doppler systolic pressure]
Postprocedure Care
1. Wipe the ultrasonic gel from the skin and remove the sphygmomanometer cuff.
2. If performing serial ABI measurements postoperatively, notify the physician for a decrease in ABI of at least 0.15 (15%) or for the loss of a previously palpable pulse or audible Doppler tone.
Client and Family Teaching
1. This test is painless.
2. This measurement helps estimate how much blood is flowing to the leg and foot.
Factors That Affect Results
1. Values may be inconsistent if the same arm is not used for every brachial pressure measurement.
2. Immediate postoperative hypotension and low body temperature may necessitate use of a Doppler scanner to locate pulse tones because pulses may not be palpable.
Other Data
1. The ABI is a good predictor of survival in clients with peripheral vascular disease. Those with ABIs less than 0.30 have significantly poorer survival than clients with ABIs of 0.31-0.91.
2. The transfer function index (TFI) has been shown to be superior to ABI in detecting vascular grafts at risk for failing. See Pulse volume recording of peripheral vasculature—Diagnostic .
3. See also Doppler ultrasonographic flow studies—Diagnostic .
ANP
See Natriuretic Peptides—Plasma .
Antegrade Pyelography— Diagnostic
Norm.
The selected ureter fills from the renal pelvis to the urinary bladder. Normal renal pelvic, ureteral, and urinary bladder contours are demonstrated radiographically after the injection of radiopaque contrast material.
Usage.
Most commonly requested in clinical scenarios where ureteral obstruction is suspected but cannot be diagnosed effectively by intravenous pyelography (IVP) or cystoscopy and retrograde pyelography. Used for detection of synchronous tumor of the upper urinary tract, ureteropelvic laceration after blunt body trauma, or ileal conduit stenosis. Frequently performed with the placement of percutaneous nephrostomy tubes in the treatment of urinary tract obstruction and analysis of ureteral stent placement.
Description.
Antegrade pyelography is an invasive radiographic procedure in which radiocontrast material is injected percutaneously into the renal pelvis. The flow of the contrast material is then observed as it progresses into the ureter and urinary bladder. Hydronephrosis or obstruction of the flow of the radiocontrast material into the urinary bladder is diagnostic of urinary tract obstruction and may be suggestive of the need to place a percutaneous nephrostomy tube.
Professional Considerations
Consent form IS required.
Risks
Allergic reaction to the radiocontrast material or anesthetic agents, bleeding (bladder clots, hematuria, perinephric hematoma), bowel perforation, infection, laceration of the renal collecting system with resulting urine leaks, pneumothorax.
Contraindications
Allergy to radiocontrast material, hemorrhagic diathesis.
Precautions
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk-benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dose to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.
Preparation
1. This test is generally performed by a urologist or an interventional radiologist in an area equipped with fluoroscopy or ultrasound equipment.
2. A formal assessment to rule out hemorrhagic diathesis (PT, PTT, bleeding time, platelet count) as well as baseline determination of hematocrit and hemoglobin is advisable. A baseline urinalysis is also often obtained. It is useful to determine if the client will permit transfusion in the event of hemorrhage. If not, it may be necessary to reconsider the procedure.
3. Orders may include a 4-hour fast from food and a sedative.
4. Vital signs (blood pressure reading, pulse rate, respiratory rate) immediately before the procedure are indicated.
5. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
Procedure
1. In the fluoroscopy or sonography suite, the position of the renal pelvis is demonstrated radiographically. A posterior vertical approach to the kidney is usually selected.
2. The flank over the renal pelvis is prepped with an iodine solution, and sterile drapes are applied to create a sterile field.
3. A 22-gauge needle is advanced into the renal pelvis under fluoroscopic or ultrasonographic guidance. Once within the collecting system, urine samples can be obtained and radiocontrast material injected to confirm the location of the needle tip within the renal pelvis.
4. At this point, a guidewire is advanced through the needle, allowing placement of larger introducer needles or urostomy catheters, or both types. Further radiocontrast material can be injected to complete the antegrade pyelogram procedure.
Postprocedure Care
1. Frequent determination of the vital signs is indicated in the immediate postprocedure period. Vital signs are generally obtained at 15-minute intervals for the first hour after the procedure and then at frequent intervals as specified by the physician performing the test.
2. Close monitoring of the urine output and observation for the development of hematuria are important. The client may have a nephrostomy bag as well as a Foley catheter bag after the pyelography, so separate records of each output source may be necessary.
3. Serial determinations of hematocrit, hemoglobin, creatinine, and serum electrolytes may be indicated.
4. If nephrostomy tubes have been placed, dressing checks and changes may be needed.
5. New fluid and antibiotic orders may need to be executed after the pyelography procedure.
Client and Family Teaching
1. The need to frequently monitor vital signs and urine output should be discussed.
2. Gross hematuria is not unusual after this procedure, and a relatively small amount of blood will produce red urine. The client should be reassured that this development generally is to be expected and does not necessarily indicate an unfavorable outcome.
3. Special positioning of the client may be required because of the nephrostomy tubes, and this should be explained to the client.
Factors That Affect Results
1. Postprocedure bleeding or infection.
2. Hematuria resulting in clotting of nephrostomy tubes.
3. Formation of bladder clots causing pain and diminished urine output.
4. Accelerated urine output after nephrostomy tube placement (post obstructive diuresis), resulting in volume depletion (hypotension, tachycardia, electrolyte abnormalities).
Other Data
1. Intravenous pyelography, CT scan, and nuclear magnetic resonance scanning are noninvasive alternative diagnostic modalities useful in the evaluation of urinary tract obstruction.
2. Renal insufficiency is a relative contraindication for the administration of intravenous radiocontrast material but is not a contraindication for antegrade or retrograde pyelography.
3. See also Retrograde pyelography—Diagnostic .
Anthrax
See Blood Culture—Blood .
Antibody Identification, Red Cell— Blood
Norm.
Requires interpretation.
Usage.
Identification of the specific nature of antibodies detected with more general antibody screens (indirect Coombs' testing). Found in clients who are homozygous for sickle cell disease.
Description.
Irregular antibodies are usually detected in clients who have had prior exposure to foreign antigens through blood transfusions or pregnancy. The presence of these irregular antibodies may cause transfusion reactions and hemolytic disease of the newborn. The exact antibody is identified when the client's serum is combined with a panel of red blood cell samples, each containing a known antigen. This test is typically performed in a blood bank or transfusion services department.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: One lavender topped or pink topped and one red topped, red/gray topped, or gold topped.
2. Note the client's age, medications, past transfusions of blood products, and number of pregnancies on the laboratory requisition.
Procedure
1. Draw a 5-mL blood sample in the lavender topped or pink topped tube.
2. Draw a 10-mL blood sample in the red topped, red/gray topped, or gold topped tube.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 24 hours.
Factors That Affect Results
1. Reject hemolyzed specimens.
Other Data
1. Identification of cold-reacting antibodies reactive at −30 degrees C may require the use of a blood warmer during transfusion.
2. Anti-D and anti-C antibodies are associated with most neonatal morbidity.
Anticardiolipin Antibody
See Antiphospholipid Antibodies—Serum .
Antideoxyribonuclease B Antibody Titer (Anti-DNase B Antibody, Streptodornase)— Serum
Norm.
Adult 85 Todd U/mL or <1 85="" :="" p="">Child <7 span="" style="white-space: pre;" years="">
<60 60="" :="" ml="" or="" p="" todd="" u="">Child ≥7 years <170 170="" :="" full="" ml="" nbsp="" or="" p="" size="" todd="" u="" view="">A fourfold increase between acute and convalescent specimens indicates infection with group A streptococci.
Increased.
Anorexia nervosa, glomerulonephritis (poststreptococcal), pharyngitis (streptococcal), poststreptococcal reactive arthritis (PSReA), pyodermic skin infections, rheumatic fever (acute), Tourette's syndrome.
Description.
Deoxyribonuclease B is an antigen produced by group A streptococci. The anti-DNase B test detects antibodies to deoxyribonuclease B, which appear when a client has a poststreptococcal infection. The levels increase after a client recovers from a group A streptococcal infection and thus are a reliable indicator of recent hemolytic streptococcal infection.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List drug therapy and previous vaccinations on the laboratory requisition.
3. Transport the specimen to the laboratory immediately. Spin and refrigerate the specimen if not tested immediately.
Procedure
1. Draw a 4-mL blood sample. Label this as the acute sample.
2. Draw a repeat titer in 2 weeks.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 48 hours.
2. Return in 2 weeks for collection of a convalescent sample.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. False-negative results may occur in hemorrhagic pancreatitis.
Other Data
1. This test is more sensitive to streptococcal pyoderma than the antistreptolysin-O (ASO) test.
2. Anti–zymogen antibody titers are a better marker for streptococcal infection associated with acute glomerulonephritis.
Antidiuretic Hormone (ADH)— Serum
Norm.
Serum Osmolarity (mOSm/L) ADH Level (pg/mL) SI Units (pmol/L)
270-280 <1 .5="" span="" style="white-space: pre;"> <1 .4="" p="">280-285 <2 .5="" span="" style="white-space: pre;"> <2 .3="" p="">285-290 1-5 0.9-4.6
290-295 2-7 1.9-6.5
295-300 4-12 3.7-11.1 View full size
Increased.
Acute intermittent porphyria, cancer (brain, intrathoracic nonpulmonary cancer, gastrointestinal cancer, gynecologic cancer, breast cancer, prostate cancer, sarcoma), cerebral infection, cerebrovascular disease, diabetes insipidus (nephrogenic), ectopic production from neoplasm, Guillain-Barré syndrome, meningitis (tuberculous), pneumonia, syndrome of inappropriate antidiuretic hormone secretion (SIADH) (caused by malignant tumors, CNS disorders, intrathoracic infections, positive-pressure ventilation), and tuberculosis (pulmonary). Drugs include anesthetics, antipsychotics, barbiturates, carbamazepine, chlorothiazide, chlorpropamide, cisplatin, clofibrate, cyclophosphamide, desmopressin, furosemide, estrogens, lithium, melphalan, morphine sulfate and other narcotic analgesics, oxytocin citrate, oxytocin injection, psychotropic drugs, thiazides, tolbutamide, tricyclic antidepressants and vidarabine, vinblastine, and vincristine sulfate.
Decreased.
Enuresis, nephrotic syndrome, pituitary diabetes insipidus, and psychogenic polydipsia. Drugs include alcohol, demeclocycline, ethyl alcohol, lithium carbonate, and phenytoin sodium.
Description.
A hormone produced by the hypothalamus and stored and released from the posterior lobe of the pituitary gland in response to increased serum osmolarity. Acts to maintain body water balance through regulation of sodium and potassium levels and vascular smooth muscle control. Release of ADH is inhibited by decreased serum osmolarity.
Professional Considerations
Consent form NOT required.
Preparation
1. See Client and Family Teaching .
2. Tube: Lavender topped, made of plastic rather than glass.
3. Notify laboratory personnel that a specimen for ADH measurement will be arriving shortly.
Procedure
1. Draw a 5-mL blood sample.
Postprocedure Care
1. Write the collection time on the laboratory requisition.
2. Transport the specimen to the laboratory for spinning within 10 minutes of collection.
Client and Family Teaching
1. Fast and refrain from stress and strenuous activity for 12 hours before the test.
2. Results are normally available in about 5 days.
Factors That Affect Results
1. Reject specimens received more than 10 minutes after collection.
2. Elevated ADH levels may be caused by physical and psychologic stress and positive-pressure mechanical ventilation. Highest levels are obtained at night. Pain, stress, exercise, and elevated blood osmolality will each cause increased secretion.
3. Decreased ADH levels may be caused by negative-pressure mechanical ventilation, recumbent position, hypoosmolar blood, and hypertension.
4. Results are invalidated if the specimen is drawn within 1 week after the client has undergone a scan using radioactive dye.
5. Glass causes degradation of ADH.
Other Data
1. None.
Anti-DNA— Serum
Norm.
Negative 0-0.9 mg of native DNA/mL of plasma or <70 iu="" ml="" p="">Borderline SLE 70-200 IU/mL View full size
Increased.
Autoimmune disorder (1-2.5 mg/mL), myasthenia gravis, rheumatoid arthritis, sclerosis (systemic), Sjögren's syndrome, systemic lupus erythematosus (SLE) nephritis, SLE (active = 10-15 mg/mL; remission = 1-2.5 mg/mL), and non-Hodgkin's lymphoma. Drugs include estrogen.
Description.
Detects the presence of antibodies to native deoxyribonuclease that indicate autoimmune activity. The test may be used to monitor the progression (increasing levels) and remission (decreasing levels) of SLE.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, lavender topped, or gray topped (depending on specific laboratory requirements).
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Results are invalid if the specimen is drawn less than 1 week after the client received a scan using radioactive dye.
2. Procainamide and hydralazine can induce anti-DNA antibodies.
Other Data
1. In the past it was unnecessary to test clients with negative antinuclear antibodies (ANAs). However, there exists a group of ANA-negative lupus clients who have elevated anti-DNA levels.
2. In SLE, immune complexes of anti-DNA may be deposited in the brain, heart, kidneys, and synovial tissue.
Anti-DNase B Antibody
See Antideoxyribonuclease B Antibody Titer—Serum .
Antigen Detection Test
See Respiratory Antigen Panel—Specimen .
Antihemophilia Factor
See Factor VIII—Blood .
Antihyaluronidase (AH) Titer— Serum
Norm.
<128 ml.="" p="" u="">
A fourfold increase between acute and convalescent samples is significant, regardless of the magnitude of the titer.
Increased.
Recent group A streptococcal disease, glomerulonephritis (acute), and rheumatic fever (acute).
Description.
Hyaluronidase is an extracellular enzyme antigen produced by group A beta-hemolytic streptococci. This test measures levels of antibodies to hyaluronidase that appear in clients who are recovering from group A beta-hemolytic streptococcal infections. Levels increase after a client recovers from a group A beta-hemolytic streptococcal infection (about the second week of infection) and decrease 3-5 weeks after infection. Levels are thus a reliable indicator of recent group A beta-hemolytic streptococcal infection.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List drug therapy and all previous vaccinations on the laboratory requisition.
Procedure
1. Draw a 5-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory immediately. Spin and refrigerate the specimen if not tested immediately.
Client and Family Teaching
1. Return in 1-3 weeks for convalescent samples to be drawn.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Drugs that may cause falsely suppressed results include antibiotics and corticosteroids.
3. Falsely elevated results may occur in the presence of hyperlipoproteinemia.
Other Data
1. A better test than the antistreptolysin-O (ASO) test for detecting antibodies in acute glomerulonephritis, which follows a streptococcal pyoderma.
Anti-La/SS-B Test— Diagnostic
Norm.
Negative.
Usage.
Differential diagnosis of systemic lupus erythematosus (SLE), Sjögren's syndrome, and mixed connective tissue disease.
Positive.
Antinuclear antibody (ANA)–negative lupus, congenital heart block, neonatal lupus, Sjögren's syndrome. Drugs include terbinafine.
Description.
Anti-La/SS-B is an autoantibody characteristically found in high titers in clients with primary Sjögren's syndrome or Sjögren's syndrome with SLE. The SS-B(La) are antibodies directed against ribonucleic acid (RNA) protein particles that are a cofactor in RNA polymerase III. Although electrophoresis is the most sensitive method for detecting anti-La/SS-B, immunodiffusion is the method most commonly used.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. None found.
Other Data
1. This test is less sensitive but more specific for primary Sjögren's syndrome than the anti-Ro/SS-A test.
2. The presence of both anti-La/SS-B and anti-Ro/SS-A antibodies is generally associated with a milder form of SLE.
3. Clients who are positive for antinuclear antibody and who have SS-A, but not SS-B, are likely to have nephritis.
Antimicrosomal Antibody
See Thyroid Peroxidase Antibody—Blood .
Antimitochondrial Antibody (AMA)— Blood
Norm.
Negative at 1 : 5 to 1 : 10 dilution.
<1 .0="" units="Negative.</p">
1.0-1.3 Units = Inconclusive.
>1.3 Units = Positive.
Suggestive of primary biliary cirrhosis >1 : 20
Probable primary biliary cirrhosis; biopsy recommended >1 : 80
Diagnostic of primary biliary cirrhosis >1 : 160 View full size
Increased.
Acute cholestatic hepatitis, autoimmune diseases, carbon monoxide poisoning, chronic active hepatitis (20% of clients), cryptogenic cirrhosis, gastric adenocarcinoma, hepatitis C, jaundice (drug induced), myasthenia gravis, and primary biliary cirrhosis.
Decreased or Absent.
Autoimmune cholangitis, drug-induced cholestatic jaundice, extrahepatic obstructive biliary disease, status post liver transplantation for primary biliary cirrhosis, sclerosing cholangitis, and viral hepatitis.
Description.
An immunofluorescent test that detects and measures autoimmune immunoglobulins of the IgG type (antibodies) to mitochondria that attack organs, which then expend large amounts of energy. A majority of clients with primary biliary cirrhosis have antimitochondrial antibodies. This test is usually performed with the test for anti–smooth muscle antibodies to aid in differentiating primary biliary cirrhosis and chronic active hepatitis from diffuse, extrahepatic biliary obstruction and other liver diseases.
Professional Considerations
Consent form NOT required.
Preparation
1. See Client and Family Teaching .
2. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed or visibly lipemic specimens.
2. Results are unreliable for clients using oxyphenisatin.
3. False-positive results may occur in clients with syphilis.
Other Data
1. AMA may be profiled into serologic subtypes.
Antimyocardial Antibody— Serum
Norm.
Negative.
Positive.
Cardiomyopathy (idiopathic), Dressler's syndrome, fibrosis (endomyocardial), status after myocardial infarction, myocarditis, pericarditis (idiopathic), pleural fluid analysis, postcardiac injury syndrome (PCIS), postpericardiotomy syndrome, postthoracotomy syndrome, rheumatic fever, rheumatic heart disease, systemic lupus erythematosus, and thoracic injury.
Description.
Antimyocardial antibody is an antibody to an organ-specific antigen in myocardial tissue that causes autoimmune damage to the heart and may be detected in serum before the appearance of clinical symptoms. The myocardial antigenic determinant is also believed to be a characteristic of streptococci because the antibodies may appear in rheumatic fever or after a streptococcal infection. This test uses an indirect immunofluorescence method by treatment of extracts of animal cardiac tissue with the client's serum and observation for the development of antigen-antibody immune complexes. Positive results are reported in titers of the lowest dilution at which the immune complexes can be detected, and decreasing titers correlate with response to treatment. This test is used in the detection of an autoimmune cause for the above-listed conditions and for monitoring therapeutic response to treatment for the above-listed conditions.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 5-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Results are normally available within 48 hours.
Factors That Affect Results
1. No factors known to affect results.
Other Data
1. Myocardial antibodies do not usually occur in clients with coronary insufficiency alone, but do occur in clients who also have had a myocardial infarction.
2. Pleural fluid can be analyzed for antimyocardial antibody to determine postcardiac injury syndrome (PCIS) and help exclude other diagnoses.
Antineutrophil Cytoplasmic Antibody Screen (ANCA, Cytoplasmic Neutrophil Antibodies)— Serum
Norm.
Screen Titer
p-ANCA Negative <1 20="" :="" p="">c-ANCA Negative <1 20="" :="" full="" nbsp="" p="" size="" view="">Increased c-ANCA.
Human immunodeficiency virus, microscopic polyangiitis, Wegener's granulomatosis.
Increased p-ANCA.
Churg-Strauss syndrome, Crohn's disease, Felty's syndrome, hepatitis (50% to 80% of clients, chronic), systemic lupus erythematosus (SLE), microscopic polyangiitis, primary sclerosing cholangitis (72% to 80% of clients), rheumatoid arthritis, ulcerative colitis (72% to 80% of clients).
Description.
Neutrophils are very active in the body's immune defenses by releasing proteolytic enzymes to phagocytose bacteria. In conditions characterized by necrotizing vasculitis, antineutrophil cytoplasmic antibodies (ANCAs) are present. ANCAs are autoimmune antibodies directed against the lysosomal enzymes in neutrophil granules. ANCAs occur in two staining patterns. The p-ANCA stains in a perinuclear pattern, similar to that of the antinuclear antibodies. The c-ANCA demonstrates a classical granular cytoplasmic staining pattern. p-ANCA and c-ANCA are present in most (>90%) clients with systemic necrotizing vasculitis and in few clients with collagen-type vascular disease. Thus this test helps diagnose vasculitis. p-ANCA is also used to help diagnose inflammatory bowel or liver disease.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped.
Procedure
1. Collect a 3-ml blood sample.
Postprocedure Care
1. Deliver specimen to the laboratory. Separate and refrigerate serum until testing.
2. Specimens are tested by staining and then examining the slide for characteristic C and P patterns. When samples stain positive, they are then serially diluted to determine the titer.
Client and Family Teaching
1. Results are not usually available for 3-5 days.
Factors That Affect Results
1. Both IgM and IgG antibodies must be tested to avoid a false-negative result.
2. Results are unreliable if formalin is used to fix the slides.
3. Immunofluorescence titers usually, but do not always, decrease with remission.
4. Reject hemolyzed lipemic specimen.
Other Data
1. The c-ANCA sensitivity and specificity for Wegener's granulomatosis are 90% and 80%, respectively.
2. p-ANCA is also known as “UC-ANCA” and “X-ANCA.”
Antinuclear Antibody (ANA)— Serum
Norm.
Negative at 1 : 20 dilution.
Positive.
Autoimmune pancreatitis, autoimmune thyroid disease, cancer (hepatic or pulmonary), dermatopolymyositis, hepatitis (chronic active, lupoid), mixed connective tissue disease, myasthenia gravis, polymyositis, pulmonary fibrosis (idiopathic), Raynaud's syndrome, rheumatoid arthritis, scleroderma, some healthy older adults, systemic lupus erythematosus (SLE), systemic sclerosis, and Sjögren's syndrome. Drugs include beta-adrenergic blockers, carbamazepine, lovastatin, methyldopa, nitrofurantoin sodium, penicillamine, and tocainide.
Description.
Antinuclear antibodies are antibodies the body produces against its own DNA and nuclear material that cause tissue damage and characterize autoimmune diseases. Highest titers occur in SLE. The immunofluorescent procedure results in four characteristic staining patterns, which help differentiate the type of connective tissue disease. These patterns and their specificities include the homogeneous pattern specific for SLE and other connective diseases; the peripheral pattern specific for SLE; the speckled pattern specific for mixed connective disease, SLE, Sjögren's syndrome, polymyositis, dermatomyositis, and scleroderma; and the nucleolar pattern specific for scleroderma and Sjögren's syndrome. These patterns, however, are not diagnostic of the various diseases. If positive results are obtained, the anti-DNA test should be performed to aid differentiation of SLE.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. List drug therapy on the laboratory requisition.
3. See Client and Family Teaching .
Procedure
1. Draw a 2-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. False-negative results may be caused by drug therapy with corticosteroids.
3. Drugs that may cause false-positive results from a drug-induced syndrome resembling SLE include acetazolamide, aminosalicylic acid, carbidopa, chlorothiazide, chlorpromazine, clofibrate, diphenylhydantoin, ethosuximide, gold salts, griseofulvin microsize, griseofulvin ultramicrosize, hydralazine hydrochloride, hydroxytryptophan, isoniazid, mephenytoin, methyldopa, methyldopate hydrochloride, methylthiouracil, methysergide maleate, oral contraceptives, penicillin, phenylbutazone, phenytoin, primidone, procainamide hydrochloride, propylthiouracil, quinidine gluconate, quinidine polygalacturonate, quinidine sulfate, reserpine, streptomycin sulfate, sulfadimethoxine, sulfonamides, tetracyclines, thiouracil, and trimethadione.
4. Pregnancy or therapeutic exposure to UV radiation can increase ANA levels.
Other Data
1. The peroxidase method may be used, but patterns are not obtained.
2. In children with musculoskeletal or dermatologic disease, the prognosis of children who have positive ANA test results in the absence of autoimmune conditions is excellent.
3. Persons more than 60 years of age have a 20% chance of a positive test.
4. Up to one third of first-degree relatives of clients with SLE have a positive ANA, though they are healthy.
Anti-Parietal Cell Antibody
See Parietal Cell Antibody—Blood .
Antiphospholipid Antibodies (APAs)— Serum
Norm.
Negative.
Positive.
Anticardiolipin syndrome (primary, secondary), antiphospholipid (Hughes syndrome), Behçet's disease, cerebral palsy, chorea, diabetic muscle infarction, epilepsy, essential thrombocythemia, giant cell arteritis, human immunodeficiency virus (HIV), in vitro fertilization and embryo transfer failures, moyamoya, polymyalgia rheumatica, preeclampsia, renal allograft failure, retinal occlusive vasculopathy, syphilis, temporal arteritis, thrombosis (systemic venous), varicella zoster virus infection. Drugs include minocycline.
Description.
Antiphospholipid antibodies (APAs) constitute a family of immunoglobulins active against phospholipids. Phospholipids are complex triglyceride esters containing long-chain fatty acids, phosphoric acid, and nitrogenous bases. The group includes fatty compounds, such as lecithin, found in animal and plant cells. The APA family is composed of the anticardiolipin antibodies (ACAs), lupus anticoagulant (LA), and antibodies that cause biologic false-positive results in syphilis serologic tests. ACA and LA have been described as occurring in thromboses, autoimmune disease, infectious diseases, and neoplastic disease. An APA syndrome that occurs during pregnancy includes loss of the fetus, systemic thromboses, and thrombocytopenia. The pathophysiology of fetal loss is not clearly known, but several theories have been suggested. Clients with APA syndrome are treated with long-term oral anticoagulation therapy.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available within 48 hours.
2. This test detects antibodies that bind to fatty substances in your body. It helps identify an illness called “antiphospholipid syndrome” or “anticardiolipin syndrome,” in which the blood clots faster than normal. It is important to identify and treat this syndrome because it can lead to a greater risk for fetal death and a higher incidence of stroke, heart attack, and blindness.
Factors That Affect Results
1. Levels vary, depending on which commercial kit is used for this test, because the assays are not yet standardized.
Other Data
1. In women with previous fetal loss who have received prophylactic treatment during subsequent pregnancy, the live birth rate is 70%. Treatment has included antiplatelet drugs, immunosuppressives, and/or anticoagulants including combination therapy with aspirin and heparin.
2. Antiphospholipid antibodies are found in pediatric clients with SLE who have thrombotic events.
Antiplatelet Antibody
See Platelet Antibody—Blood .
Antiribonucleoprotein Test
See Anti-RNP Test—Diagnostic .
Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)— Diagnostic
Norm.
Negative or <20 p="" units.="">
Inconclusive.
20-49 units.
Positive.
≥50 units.
Usage.
Assists in differentiating the type of autoimmune disease occurring. Highest titers (≥1 : 10,000) are suggestive of mixed connective tissue disease such as Raynaud's phenomenon. Positive in cytomegalovirus infection, neonatal lupus erythematosus, Sjögren's syndrome, systemic lupus erythematosus.
Description.
An antinuclear antibody present in over 94% of mixed connective tissue autoimmune disease detected by an immunofluorescent procedure. Immunofluorescence results in characteristic staining patterns that help differentiate the type of connective tissue disease occurring. Anti-RNP antibodies are associated with a speckled pattern and occur in almost all clients with mixed connective tissue syndrome and about one fourth of clients with scleroderma and discoid and systemic lupus erythematosus. High titers are usually accompanied by clinical symptoms of mixed connective tissue disease. A positive test is specific for mixed connective tissue disease when results of other autoantibody testing are negative.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Transport the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed, lipemic, or contaminated specimens.
2. False-negative results may be caused by drug therapy with corticosteroids.
3. Drugs that may cause false-positive results because of a drug-induced syndrome resembling systemic lupus erythematosus (SLE) include acetazolamide, aminosalicylic acid, carbidopa, chlorothiazide, chlorpromazine, clofibrate, diphenylhydantoin, ethosuximide, gold salts, griseofulvin microsize, griseofulvin ultramicrosize, hydralazine, hydrochloride, hydroxytryptophan, isoniazid, mephenytoin, methyldopa, methyldopate hydrochloride, methyl-thiouracil, methysergide maleate, oral contraceptives, penicillin, phenylbutazone, phenytoin, primidone, procainamide hydrochloride, propylthiouracil, quinidine gluconate, quinidine polygalacturonate, quinidine sulfate, reserpine, streptomycin sulfate, sulfadimethoxine, sulfonamides, tetracyclines, thiouracil, and trimethadione.
Other Data
1. Titer is determined by counterimmunoelectrophoresis (CIE).
Anti-Ro/SS-A Test— Diagnostic
Norm.
Negative or <20 p="" units.="">
Inconclusive.
20-49 units.
Positive.
≥50 units.
Positive.
ANA-negative lupus, complete congenital heart block, neonatal lupus, polymyositis/dermatomyositis, and Sjögren's syndrome.
Description.
Anti-Ro/SS-A is an autoantibody to the cytoplasmic RNA Ro antigen characteristically found in high titers in clients with primary Sjögren's syndrome or Sjögren's syndrome with systemic lupus erythematosus (SLE). Although electrophoresis is the most sensitive testing method for detection of these antibodies, the most common method used is immunodiffusion. This test is used in the differential diagnosis of SLE, Sjögren's syndrome, and mixed connective tissue disease. The antibody is present in over 70% of Sjögren's syndrome, 30%-40% of SLE, and only 5%-10% of progressive systemic sclerosis.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Send the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject lipemic, hemolyzed, or contaminated specimens.
Other Data
1. This test is more sensitive but less specific for primary Sjögren's syndrome than the anti-La/SS-B test.
2. The presence of both anti-La/SS-B and anti-Ro/SS-A antibodies is generally associated with a milder form of SLE.
3. Clients who are positive for antinuclear antibody and who have SS-A, but not SS-B, are likely to have nephritis.
4. African-Americans are at increased risk for the presence of anti-Ro antibodies and SLE.
Anti-Sm Test (Extractable Nuclear Antigen)— Diagnostic
Norm.
Negative.
Usage.
Assists in differentiating the type of autoimmune disease occurring. The presence of antibodies specific against Sm is strongly suggestive of systemic lupus erythematosus (SLE) when other autoantibodies are negative. Increases in Sm antibody levels are seen in arthritis, heart-related diseases, Raynaud's phenomenon, and SLE.
Description.
An antinuclear antibody active against acidic nuclear proteins, present in autoimmune disease detected by an immunofluorescent procedure. Immunofluorescence results in characteristic staining patterns that help differentiate the type of connective tissue disease occurring. Anti-Sm antibodies are associated with a speckled pattern and occur in clients with mixed connective tissue syndrome and in about one fourth of clients with scleroderma, discoid lupus erythematosus, and SLE.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Send the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed, lipemic, or contaminated specimens.
2. False-negative results may be caused by drug therapy with corticosteroids.
3. Drugs that may cause false-positive results arising from a drug-induced syndrome resembling SLE include acetazolamide, aminosalicylic acid, carbidopa, chlorothiazide, chlorpromazine, clofibrate, diphenylhydantoin, ethosuximide, gold salts, griseofulvin microsize, griseofulvin ultramicrosize, hydralazine hydrochloride, hydroxytryptophan, infliximab, isoniazid, mephenytoin, methyldopa, methyldopate hydrochloride, methylthiouracil, methysergide maleate, oral contraceptives, penicillin, phenylbutazone, phenytoin, primidone, procainamide hydrochloride, propylthiouracil, quinidine gluconate, quinidine polygalacturonate, quinidine sulfate, reserpine, streptomycin sulfate, sulfadimethoxine, sulfonamides, tetracyclines, thiouracil, and trimethadione.
Other Data
1. There is a clinical association of this antibody titer with vasculitis.
2. Not useful as a screening test for lupus because results must be interpreted in consideration of other antibody testing.
Anti–Smooth Muscle Antibody— Serum
Norm.
Negative at titer <1 20.="" :="" p="">
Increased.
Asthma (intrinsic) (positive at titer <1 10="" 1="" 320="" 40="" 50="" 70="" 80="" :="" active="" acute="" age.="" and="" at="" autoimmune="" biliary="" carcinoma="" chronic="" cirrhosis="" clients="" cryptogenic="" damage="" drug="" fever="" hepatitis="" hepatocellular="" in="" includes="" infectious="" infiltrative="" liver="" lupoid="" majority="" malignancies="" minocycline.="" mononucleosis="" of="" p="" pancreatitis="" positive="" rare="" titer="" titers="" to="" tumors="" viral="" with="" years="" yellow="">
Description.
An immunofluorescent test that detects and measures autoimmune immunoglobulins (antibodies) in smooth muscle that occur in chronic active hepatitis and also in response to damaged liver cells. This test is usually performed with the test for antimitochondrial antibodies as an aid in differentiating primary biliary cirrhosis and chronic active hepatitis from diffuse, extrahepatic biliary obstruction and other liver diseases.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. Send the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast for 8 hours before sampling.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Antinuclear antibody impairs interpretation of results.
Other Data
1. This test is not diagnostic. A liver biopsy is recommended.
2. Low titers may occur with infectious mononucleosis, rheumatoid arthritis, liver disease, and malignancies.
Antisperm Antibodies
See Infertility Screen—Specimen .
Antistreptococcal Enzyme
See Antistreptolysin-O Titer—Serum .
Antistreptolysin-O (ASO) Titer— Serum
Norm.
Adults <330 iu="" ml="" p="">Children
<2 span="" style="white-space: pre;" years=""> <200 iu="" ml="" p="">2-5 years <240 iu="" ml="" p="">5-19 <330 full="" iu="" ml="" nbsp="" p="" size="" view="">A fourfold rise in titer between acute and convalescent specimens is diagnostically significant.
Increased.
Acute poststreptococcal endocarditis, acute poststreptococcal glomerulonephritis (500-5000 Todd U/mL), pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), reactive arthritis, rheumatic fever (inactive is <250 500-5000="" active="" chorea="" disease="" elevations="" fever="" is="" ml="" p="" recent="" s="" scarlet="" small="" streptococcal="" sydenham="" syndrome.="" todd="" tourette="" u="">
Decreased.
Not clinically significant. Levels may decrease with antibiotic therapy.
Description.
Antibody to the streptolysin-O enzyme produced by Lancefield group A beta-hemolytic streptococci. These titers rise about 7 days after infection, peak at 3-5 weeks, and then gradually return to baseline level over the next 6-12 months. Because ASO titers remain elevated in clients with poststreptococcal infections, the test is used to determine whether symptoms such as joint pains, rheumatic fever, or glomerulonephritis are of a poststreptococcal disease origin.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Draw a 4-mL blood sample.
2. Draw a repeat titer in 10-14 days.
Postprocedure Care
1. Send the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Repeated ASO titers every 10-14 days are recommended. When poststreptococcal disease occurs, titers begin to rise 1 week after the initial streptococcal infection and peak 2-4 weeks later; 6 months to 1 year is required for postinfection levels to return to the baseline level.
2. Results may not be available for several days if testing is not performed on site.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. Falsely suppressed results may be caused by nephrotic syndromes, antibody deficiency syndromes, or drug therapy with corticosteroids or antibiotics.
3. Falsely elevated results may be caused by contaminated serum, hyperbetalipoproteinemia, hypercholesterolemia, hyperglobulinemia, lipemic serum, or liver disorders.
4. The persistent presence of an antibody from a previous but not recent infection may mildly increase titers. Only very high titers are indicators of recent infection (such as adult, >250 Todd U; child, >333 Todd U).
Other Data
1. Up to 20% of clients with poststreptococcal glomerulonephritis may have normal titers. The anti-DNase-B test is recommended to improve specificity.
2. Increased C-reactive protein and ASO are some of the key factors in the development of chronic gingivitis.
3. See also Antihyaluronidase titer—Serum ; Streptozyme—Blood .
Antithrombin III (AT-III) Test— Diagnostic
Norm.
SI Units
Plasma 21-30 mg/dL
85-115% of standard >50% of control value 210-300 mg/L
Serum 15-35% lower than plasma values 0.85-1.15
Immunologic 17-30 mg/dL
Functional 80-130% View full size
Increased.
Factor deficiency (V, VII), hemophilia (A, B), hepatitis (acute), inflammation, jaundice (obstructive), menstruation, nephrotic syndrome, renal transplantation, vitamin K deficiency. Drugs include anabolic steroids, androgens, bishydroxycoumarin, gemfibrozil, oral contraceptives (containing progesterone), progesterone, and warfarin sodium.
Decreased.
Alcoholic liver disease, arteriosclerosis, burns, carcinoma, cardiovascular disease, cerebrovascular accident, cirrhosis, congenital antithrombin III deficiency, deep vein thrombosis, dengue shock syndrome, diabetes mellitus (type II), disseminated intravascular coagulation, hepatic disease (abscess, hepatitis), homocystinuria, hypercoagulation, liver failure (chronic), liver transplantation, malignancy (extensive), malnutrition, nephrotic syndrome, status post partial hepatectomy, postoperatively, postpartum, preeclampsia, pulmonary embolism, septicemia, thromboembolism, veno-occlusive disease (VOD). Drugs include estrogens, fibrinolytics, gestodene, heparin calcium, heparin sodium, L-asparaginase, methylprednisolone, and oral contraceptives (containing estrogen).
Description.
A naturally occurring protein, IgG (immunoglobulin G), probably synthesized by the liver, that inhibits coagulation through inactivation of thrombin and other factors. The action of AT-III is catalyzed by heparin. Hereditary AT-III deficiency is an autosomal dominant disease that predisposes clients to venous thrombosis and heparin resistance.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: 2.7 or 4.5-mL blue topped.
2. See Client and Family Teaching .
Procedure
1. Draw 2.4 mL of blood for a 2.7-mL tube or 4.0 mL of blood for a 4.5-mL tube.
Postprocedure Care
1. Send the specimen to the laboratory for immediate spinning.
Client and Family Teaching
1. Fast, except for water, for 10-12 hours before testing.
Factors That Affect Results
1. Reject hemolyzed, lipemic, or contaminated specimens.
2. Results are normally available within 3-5 days.
Other Data
1. Levels of 50% to 75% indicate moderate risk for thrombosis, whereas levels under 50% indicate significant risk for thrombosis.
2. A low level in clients taking warfarin indicates that the warfarin is not working effectively.
3. AT-III is positively correlated to hematoma volume in hypertensive intracerebral hemorrhage (HICH).
Antithyroglobulin Antibody
See Thyroid Antithyroglobulin Antibody—Serum .
Antithyroid Microsomal Antibody
See Thyroid Peroxidase Antibody—Blood .
Apexcardiography (ACG)— Diagnostic
Norm.
Normal a wave, c point, e point, o point, rf wave, f point, sf wave, and stasis.
Cardiac Abnormalities Changes That May Be Found in Apexcardiographic Recording
Aortic valve stenosis Large a wave; apical impulse occurring late in systole
Atrial fibrillation Absent a wave; steepened slope of rf wave
Cardiac failure Apical impulse occurring late in systole
Coronary artery disease Apical impulse occurring late in systole
Mitral regurgitation Steepened slope of rf wave
Mitral stenosis Absent a wave; shallow slope of rf wave
Hypertension Large a wave; apical impulse occurring late in systole
Idiopathic hypertrophy Large a wave subaortic stenosis
Left ventricular aneurysm Apical impulse occurring late in systole
Myocardial ischemia or pericarditis Apical impulse occurring late in systole infarction; steepened slope of rf wave View full size
Usage.
Helps diagnose heart abnormalities and arterial hypertension. In conjunction with phonocardiography, helps to identify heart sounds.
Description.
Apexcardiography is a method to transfer cardiac movement and pulsations into electrical energy by a transducer and produce a graphic recording of waveforms that characterize the status of the heart. The test takes less than hour to perform.
Professional Considerations
Consent form NOT required.
Preparation
1. Remove jewelry and any metal objects.
2. The client should disrobe above the waist.
Procedure
1. The client is placed in a left oblique position, and electrocardiographic limb leads are applied. The transducer tip, covered with electroconductive gel, is strapped in place in contact with the point of maximum impulse at the apex of the heart.
2. Apexcardiographic recordings are made as the client lies motionless and performs isometric hand-clenching exercises, which increase systemic vascular resistance.
Postprocedure Care
1. Remove transducer and limb leads. Cleanse the electroconductive gel off the transducer and off the client's chest.
Client and Family Teaching
1. The test is painless.
2. Slow, even respirations promote the most accurate test results. You should not talk or move during the procedure.
3. You will be asked to isometrically clench your fists, which means clenching them and then squeezing them and holding them tightly shut.
Factors That Affect Results
1. Implantable metal devices in the chest wall, such as venous access devices, do not interfere with the test as long as leads are not placed directly over the metal device.
Other Data
1. This test is rarely used due to the availability of echocardiogram and nuclear medicine testing.
Apnea Hypopnea Index
See Polysomnography—Diagnostic .
Apnea Test— Diagnostic
Negative test (absence of brain death).
Spontaneous respiratory effort occurs after mechanical ventilation is stopped.
Positive test (presence of brain death).
Absence of spontaneous respiratory effort throughout test (up to 8 minutes for adults and up to 15 minutes for pediatrics), Pa co 2 ≥60 mm Hg or 20 mm Hg higher than baseline value.
Usage.
Determination of the absence (or presence) of spontaneous breathing when one is testing for brain death; evaluation of the intracranial hemodynamic status in carotid occlusive disease.
Description.
The apnea test is part of a neurologic evaluation that tests for the respiratory reflex in clients suspected of having brain death. It is performed with a full neurologic examination, clinical history that includes a central nervous system event, and other confirmatory tests to determine brain death. Brain death is the term used when the entire brain, including the brainstem, has irreversibly stopped functioning. Brain death cannot be determined in clients receiving neuromuscular blockers, or with low core-body temperatures (such as ≤ 32.2 degrees C).
Professional Considerations
Consent form recommended from spokesperson for the client.
Risks
Cardiac arrest, pneumoperitoneum, pneumothorax.
Contraindications
Use for purposes other than those described in the previous discussion is contraindicated.
Preparation
1. Obtain and document baseline Pa co 2 value.
2. Determine if client meets requirements for apnea testing:
i. P co 2 = 40 mm Hg
ii. Mean arterial pressure (MAP) >54 mm Hg
iii. Positive fluid balance in previous 6 hours
iv. Absence of the possibility of acute drug or alcohol intoxication
v. Absence of the presence of any centrally acting drugs that could depress respiration
3. Obtain a pulse oximeter, ice, oxygen T-piece, and arterial blood gas kit.
Procedure
1. Position pulse oximetry probe on client. Set heart rate, blood pressure, and respiratory rate alarms. Monitor all throughout the test.
2. Preoxygenate client with 100% oxygen for 10 minutes.
3. Remove client's gown or clothing from the chest and abdominal area to allow visualization of respiratory muscle efforts.
4. Discontinue mechanical ventilation. Apply oxygen through a T-piece at 6 L/min. Monitor for spontaneous respiratory effort.
i. If no respiratory effort is noted after 5-8 minutes, obtain an arterial blood gas sample and restart mechanical ventilation.
ii. Observe chest for spontaneous respirations or any respiratory effort.
iii. Discontinue the test if any of the following occur:
(1) Presence of spontaneous respiratory effort
(2) Hemodynamic instability
5. Test is repeated at least 6-12 hours later.
Postprocedure Care
1. Document procedure, including methodology, length of apneic time, baseline and ending Pa co 2 values, stability of vital signs, and apneic status.
2. For positive tests, request organ donation, as and when appropriate.
Client and Family Teaching
1. Organ and tissue donation rates are higher when families or significant others receive a careful and thorough explanation of the concept of brain death.
Factors That Affect Results
1. Pa co 2 rises approximately 3 mm Hg each minute while the client is apneic and not receiving mechanical ventilation.
2. Results must be interpreted with extreme caution in clients with brain injury. Caution should be used in determining brain death when the cause of the brain injury is not known and in high cervical spine fracture in which there is damage to the spinal cord.
3. Posturing may make detection of respiratory effort impossible.
Other Data
1. The neurologic examination in brain death reveals the absence of spontaneous reflexes, absence of response to pain, and absence of brainstem reflexes, including the respiratory reflex.
Apolipoprotein A-I (Apoprotein-A, Apo-A)— Plasma
Norm.
Values are 5% to 10% higher in African-Americans.
Age Female Male
mg/dL SI Units (g/L) mg/dL SI Units (g/L)
Adult
20-29 years 80-184 0.80-1.84 81-153 0.81-1.53
30-39 years 83-187 0.83-1.87 79-155 0.79-1.55
40-49 years 93-181 0.93-1.81 100-140 1.00-1.40
50-59 years 76-204 0.76-2.04 81-169 0.81-1.69
60-65 years 122-214 1.22-2.14 86-166 0.86-1.66
Child
Birth 38-106 0.38-1.06 41-93 0.41-0.93
0.5-4 years 60-148 0.60-1.48 67-163 0.67-1.63
5-7 years 90-151 0.90-1.51 92-151 0.92-1.51
8-9 years 94-151 0.94-1.51 96-151 0.96-1.51
10-11 years 92-151 0.92-1.51 96-151 0.96-1.51
12-13 years 83-146 0.83-1.46 88-151 0.88-1.51
14-15 years 96-146 0.96-1.46 85-139 0.85-1.39
16-17 years 96-151 0.96-1.51 83-146 0.83-1.46 View full size
Apolipoprotein B/A Ratio
Coronary Atherosclerotic Risk Female Male
Average risk 0.6 0.7
Two times average risk 0.9 0.9
Three times average risk 1.0 1.0 View full size
Increased.
Not clinically significant. Familial hyperalphalipoproteinemia. Drugs include carbamazepine, chlorinated hydrocarbons, clofibrate, deflazacort, estrogen, ethyl alcohol, exercise, gemfibrozil, hormone replacement therapy of conjugated estrogen and medroxyprogesterone or 17-beta-estradiol/desogestrel, lovastatin, niacin, oral contraceptives (containing estrogen), phenobarbital, phenytoin, pravastatin, simvastatin, weight-reduction diet. Ingestion of beef increases apolipoprotein A-I.
Decreased.
Alzheimer's disease, atherosclerosis, cholestasis, coronary artery disease, diabetes mellitus (poorly controlled), hepatectomy, hepatocellular abnormalities, hypertriglyceridemia, hypoalphalipoproteinemia, ischemic coronary disease, lipoprotein lipase cofactor deficiency, myocardial infarction, nephrotic syndrome, polycystic ovary syndrome (PCOS), renal failure (chronic), stroke. Drugs include androgens, beta-adrenergic receptor blocking agents, diuretics, probucol, progestins, and Synthroid.
Description.
An inherited alpha 1 -globulin that is the major protein component (70%) of high-density lipoprotein (HDL). It is synthesized in the liver and small intestine and is essential for the transport of peripheral cholesterol to the liver for eventual excretion. Variants of the APOA1 gene have been linked to several types of amyloidosis. Calculation of the ratio of apolipoprotein A-I to apolipoprotein B and plasma levels of apo A-I are the strongest predictors, more useful than HDL cholesterol level, for identifying clients at risk for coronary artery disease.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Several testing methods are used to measure apolipoprotein A-I. Clarify the proper blood-drawing procedure with the individual laboratory.
3. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Fast for 12 hours before testing.
2. Refrain from smoking for 4 hours before testing.
3. A ratio of apolipoprotein A to apolipoprotein B is sometimes used to predict risk of coronary heart disease.
Factors That Affect Results
1. Reject hemolyzed or lipemic specimens.
2. Apolipoprotein A-I levels rise during acute illness.
3. Levels are decreased in smokers and in clients who consume high-carbohydrate or high–polyunsaturated fat diets.
Other Data
1. Apolipoprotein levels remain stable after acute ischemic stroke.
Apolipoprotein B (Apoprotein B, Apo B)— Plasma
Norm.
Age Female Male
mg/dL SI Units (g/L) mg/dL SI Units (g/L)
Adult 86-159 0.86-1.59 96-174 0.96-1.74
Child
Birth 11-31 0.11-0.31 11-31 0.11-0.31
0.5-4 years 23-75 0.23-0.75 23-75 0.23-0.75
5-7 years 49-110 0.49-1.10 47-106 0.47-1.06
8-9 years 53-132 0.53-1.32 49-105 0.49-1.05
10-11 years 54-121 0.54-1.21 52-110 0.52-1.10
12-13 years 46-110 0.46-1.10 46-113 0.46-1.13
14-15 years 41-108 0.41-1.08 44-103 0.44-1.03
16-17 years 41-96 0.41-0.96 48-139 0.48-1.39 View full size
Coronary Atherosclerotic Risk Apolipoprotein B/A Ratio
Female Male
Average risk 0.6 0.7
Two times average risk 0.9 0.9
Three times average risk 1.0 1.0 View full size
Increased.
Acute illness, Alzheimer's disease, angina pectoris, anorexia nervosa, cigarette smokers, coronary heart disease (premature), Cushing's syndrome, diabetes mellitus, dysglobulinemia, hepatic disease and obstruction, hypercalcemia (infantile), hyperlipemia (familial combined), hypothyroidism, myocardial infarction, nephrotic syndrome, porphyria, pregnancy, renal failure, sexual ateliotic dwarfism, sphingolipodystrophies, stress (emotional), and Werner's syndrome.
Decreased.
Alpha-lipoprotein deficiency, anemia (chronic), hepatocellular dysfunction, heterozygous hypobetalipoproteinemia, hyperlipoproteinemia (type I), hyperthyroidism, joint inflammation, lecithin-cholesterol acyltransferase deficiency, lipoprotein lipase cofactor deficiency, malabsorption, malnutrition, myeloma, pulmonary disease (chronic), Reye's syndrome, stress (acute physical), weight-reduction diet. Drugs include orlistat (Xenical), levothyroxine (Synthroid).
Description.
A beta-globulin that is the major protein component of low-density lipoprotein (LDL) and is also found in very-low-density lipoprotein (VLDL). Functions in cholesterol synthesis and is required for the secretion into plasma of intestinal and hepatic triglyceride-rich lipoproteins. There are two Apo B glycoproteins, Apo B-48 and Apo B-100, which have different molecular weights. Apo B-48 is produced in the small intestine and Apo B-100 is produced in the liver. Calculation of the ratio of apolipoprotein A-I to apolipoprotein B is believed to be more useful than LDL cholesterol level for identifying clients at risk for atherosclerosis.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Several testing methods are used to measure apolipoprotein B. Clarify the proper blood-drawing procedure with the individual laboratory.
3. See Client and Family Teaching .
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Fast for 12 hours before testing.
2. A ratio of apolipoprotein A to apolipoprotein B is sometimes used to predict coronary risk of heart disease.
Factors That Affect Results
1. Reject hemolyzed or lipemic specimens.
2. Apolipoprotein B levels rise during acute illness.
Other Data
1. Garlic has no effect on apolipoprotein levels.
Apolipoprotein E-4 (Apo E-4) Genotyping— Plasma
Norm.
Apo E-4 allele is not present.
Usage.
Helps identify risk for, but cannot confirm, Alzheimer's disease, because the disease also occurs in those not carriers or homozygotes. Genotyping more recently piloted for determination of risk of developing Alzheimer's disease through the National Institutes of Health. NOT useful for monitoring disease progression.
Description.
Alzheimer's disease, the most common form of dementia, is characterized by the presence of senile plaques and neurofibrillary tangles. Two forms of Alzheimer's disease are known to exist. The majority (90% to 95%) are termed “late onset,” with the remaining 5% to 10% termed “early onset.” Human apolipoprotein E is a gene involved in lipoprotein, triglyceride, and cholesterol metabolism and its lipid transport protein helps to repair membranes of central and peripheral nervous system cells. Apolipoprotein E has several genetic variations, one being the apolipoprotein (Apo) E-4 allele. The Apo E4 allele is an important genetic risk factor for late-onset Alzheimer's disease, occurring more than twice as often in those with Alzheimer's disease as in control groups. The exact mechanism by which the Apo E-4 allele contributes to the development of Alzheimer's disease is not known, but there is some evidence that its action contributes to the development of plaques and neurofibrillary tangles, as well as to the loss of brain tissue volume. Carriers of the Apo E-4 allele can have up to 2.9 times greater chance and homozygotes can have up to 15 times greater chance than noncarriers of developing Alzheimer's disease. This test has low sensitivity and specificity.
Professional Considerations
Informed consent is recommended for genetic testing.
Preparation
1. Tube: Green topped.
Procedure
1. Draw a 4-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Results are normally available in 1-2 weeks.
2. Refer the client with abnormal results for genetic counseling. Refer to section in this book on “Informed Consent for Genetic Testing”.
Factors That Affect Results
1. Heparin in the specimen collection tube must be sodium heparin.
Other Data
1. This test is currently available for research and experimental purposes.
2. The Genetic Information Nondiscrimination Act of 2008 prohibits health plans from using genetic family history or genetic test results from influencing eligibility or premiums for health insurance. It also prohibits employers from using this information to influence decisions about hiring, terminating employment, or employment pay, promotions or privileges.
APTT
See Activated Partial Thromboplastin Time and Partial Thromboplastin Time—Plasma .
Arsenic— Blood, Hair, Nails or Urine
Norm.
SI Units
Whole Blood
Normal 2-23 µg/L 0.03-0.31 µmol/L
Chronic poisoning 100-500 µg/L 1.33-6.65 µmol/L
Acute poisoning >600 µg/L >7.98 µmol/L
Serum 1.7-1.54 µg/L 0.02-0.20 µmol/L
Hair
Normal levels 20-60µg/100g <8 .7="" g="" nmol="" p="">Chronic poisoning >100µg/100g >13.4 nmol/g
Nails
Normal levels 20-60µg/100g <8 .7="" g="" nmol="" p="">Chronic poisoning 90-180µg/100g 12-24 nmol/g
Urine
Normal 24 hours 0-35 µg/L or µmol/day 5-50 µg/L or 0-50 ug/day
Chronic poisoning 0.67-66.50 µmol/L 50-5000 µg/L
Acute poisoning >13.3 µmol/L >1000 µg/L View full size
Acute Poisoning Symptoms and Treatment
Symptoms.
Abdominal pain, nausea, vomiting, bloody diarrhea, thirst progressing to dehydration and fluid and electrolyte imbalance, hematuria, metallic taste, pain (gastrointestinal), renal failure, jaundice, hypoxia, convulsions, coma, and respiratory and cardiovascular collapse. May lead to death.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Induce emesis.
2. Lavage GI tract.
3. Administer saline cathartic.
4. Administer penicillamine chelation.
5. Administer dimercaprol (BAL).
6. Support hemodynamic status.
7. Replace blood lost to GI hemorrhage.
8. Both hemodialysis and peritoneal dialysis WILL remove arsenic.
Chronic Poisoning Symptoms and Treatment
Symptoms.
Abnormal erythropoiesis and myelopoiesis, alopecia (thinning of hair), anemia, basophilic stippling, delirium, diarrhea, gastrointestinal symptoms, hepatomegaly, hyperkeratosis of palms of hands and soles of feet, leukopenia, macular hypopigmentation, Mees' lines, metallic taste, peripheral neuropathy, rain drop–like skin pigmentation changes and scaling, and thrombocytopenia.
Treatment
N ote : Treatment choice(s) depend(s) on client's history and condition and episode history.
1. Avoid exposure to arsenic.
2. Remove household sources of arsenic (described below).
Increased.
Arsenic poisoning and heavy-metal poisoning/environmental exposure to arsenic, blackfoot disease, peripheral vascular disease. Herbs or natural remedies include Korean herbal medicines usually prescribed for hemorrhoids, powdered blend of folk remedies of Hmong people from Thailand, and Indian ethnic remedies for treatment of congenital retinoblastoma.
Decreased.
Not clinically significant.
Description.
Arsenic is a trace element found in all human tissues. It is also a common heavy-metal poison that combines with intracellular proteins and is rapidly removed from the blood. It may become elevated when occupational (treated wood), environmental (coal burning), or intentional usage occurs. Sixty-three percent of ingested arsenic is excreted in the urine. Arsenic is found environmentally in well water and as an ingredient of pesticides, paints, treated wood, cosmetics, and antiprotozoal medications. Arsenic inhibits sulfhydryl enzyme systems required for cellular metabolism. Workplace exposure or chronic ingestion is associated with skin, lung and other cancers
Blood specimens are used for rapid confirmation of acute poisoning and blood levels are transitory. Because it can be found in keratin, specimens of hair and nails are used to pinpoint chronic exposure to arsenic. Urine specimens are used for rapid confirmation of acute poisoning and monitoring ongoing exposure.
Professional Considerations
Consent form NOT required unless the specimen may be used for legal evidence.
Preparation
1. For blood test: Tube: Black topped or green topped (whole blood) or red topped, red/gray topped, or gold topped (serum). Also obtain a blue topped tube containing Na 2 EDTA.
2. Do NOT draw during hemodialysis.
3. For hair or nails specimen collection: Obtain scissors or nail clippers and metal-free container.
4. Screen client for the use of herbal preparations or natural remedies such as Korean red or white ginseng (Panax).
Procedure
1. The specimen should be collected and labeled in the presence of a witness if it may be used for legal evidence.
2. Draw a 10-mL blood sample. Draw a second sample in the blue topped tube to use for confirmatory testing of trace elements.
3. Hair: Collect 0.5 g of hair from the area below the posterior crown of the head. Cut a -inch-wide section close to the scalp. Trim off the proximal inch into the metal-free container.
4. Nails: Clip the ends of all 10 toenails. Collect a total of 1 g of nails (preferably toenails) in a heavy, metal-free plastic container.
5. Urine: Collect a 24-hour urine sample in a 3-L container without preservatives.
a. Discard the first morning-urine specimen. Save all urine voided in the 24-hour period, and urinate before defecating to avoid loss of urine. If any urine is accidentally discarded, discard the entire specimen and restart the collection the next day.
b. Document the quantity of urine output during the collection period. Include urine voided at the end of the 24-hour period. For catheterized clients, keep the drainage bag on ice and empty the urine into the collection container hourly.
Postprocedure Care
1. Note the exact time of specimen collection, along with the client's name, date, contents, and your signature on the tube label and laboratory requisition.
2. Have the witness sign the laboratory requisition.
3. Transport the specimen to the laboratory in a sealed plastic bag labeled as legal evidence if that is the case. Have each person handling the specimen write his or her name and time of receipt of the specimen on the laboratory requisition.
Client and Family Teaching
1. For intentional poisoning, refer the client and family for crisis intervention.
2. For chronic poisoning, the client should be taught to remove household sources of arsenic (described above).
3. Hair or nails test results are normally available after several days.
Factors That Affect Results
1. A diet rich in seafood may elevate the blood level and may show elevated concentration levels in the urine as high as 500-1500 mg/L with no apparent signs of toxicity.
2. Arsenic in toenails represents deposition of arsenic for 6 months.
3. The earliest detection of excess arsenic in hair is 2 weeks after a dose of arsenic and may persist for months or years.
4. A 10-fold increase in well water concentrations is reflected in a 2-fold increase in toenail concentration.
5. Hyperbilirubinemia and increased serum ALP are found in conjunction with arsenic in the urine.
Other Data
1. Arsenic is easily transferred to a fetus.
2. Symptoms of chronic toxicity include fatigue, weakness, diarrhea, weight loss, dermatitis, and nausea progressing to paralysis, encephalopathy, renal and hepatic damage, and respiratory tract inflammation.
3. Children exposed to high levels of arsenic in drinking water have a health risk.
ART
See Automated Reagin Test—Diagnostic .
Arterial Blood Gases
See Blood Gases, Arterial—Blood .
Arteriogram— Diagnostic
Norm.
Even filling of the arteries with radiographic dye. The artery walls show progressive narrowing without abrupt occlusions, isolated bulging, or narrow areas. No evidence of leakage of the dye into tissues, which would indicate hemorrhage. No evidence of vascular anomalies. No displacement of vessels.
Usage.
Aids diagnosis of arterial occlusion, aneurysm, abnormal vascular development, hemorrhage and transient ischemia attacks (TIAs). Helps identify areas of arterial narrowing caused by plaque buildup, degree of stenosis after myocardial infarction (MI), tumor, or vascular abnormalities. Useful preoperatively to help identify potential failing arterial bypass grafts.
Description.
An arteriogram is a radiographic examination of arteries through which radiographic contrast medium is flowing. The arteries are assessed for abnormalities in blood flow, such as narrowing or outpouching of the walls, and for collateral circulation.
Professional Considerations
Consent form IS required.
Risks
Aphasia, cerebrovascular accident, dysrhythmias, embolus, endocarditis, hematoma, hemiplegia, hemorrhage, infection, MI, paresthesia, allergic reaction to dye (itching, hives, rash, tight feeling in the throat, shortness of breath, bronchospasm, anaphylaxis, death), renal toxicity.
Contraindications
Anticoagulant therapy, bleeding disorders, thrombocytopenia, dehydration, uncontrolled hypertension, previous allergy to radiographic dye, iodine, or shellfish, renal insufficiency, and pregnancy (if iodinated contrast medium is used, because of radioactive iodine crossing the blood-placental barrier).
Preparation
1. See Client and Family Teaching .
2. Obtain baseline CBC, PT, and APTT values.
3. Remove all jewelry and metal objects.
4. The client should void just before the procedure.
5. Obtain baseline vital signs, and mark peripheral pulses.
6. Have emergency equipment readily available for anaphylaxis and cardiac arrest.
7. Just before beginning the procedure, take a “time out” to verify the correct client, procedure and site.
Procedure
1. Client is placed supine on the radiograph table.
2. A maintenance intravenous line is started.
3. The peripheral pulses are marked, and the extremity is immobilized.
4. The femoral or brachial artery area is located and cleansed with povidone-iodine solution and allowed to dry, and the surrounding area is covered with a sterile drape.
5. A local anesthetic (1% to 2% lidocaine) is injected intradermally and subcutaneously over the artery.
6. The femoral or brachial artery is punctured with a large-bore needle. A wire is passed through the needle and the needle removed over the guidewire.
7. The catheter is then inserted into the artery over the guidewire, and placement is confirmed by fluoroscopy.
8. The catheter is advanced under fluoroscopy to a location depending on the area to be examined, and radiographic dye is injected.
9. Several rapid radiographic pictures are taken of the artery and its branches during and after dye injection.
10. The catheter is removed, and sterile gauze is applied immediately, with pressure, to the site for at least 15 minutes.
Postprocedure Care
1. Apply pressure dressing to arterial puncture site.
2. The client remains on bed rest with the affected extremity immobilized for 12 hours.
3. Assess the site and dressing for hematoma or bleeding; the distal pulses for presence and strength; and color, motion, temperature, and sensation of the affected extremity every 15 minutes × 4, every half hour × 4, then every hour × 4, and then every 4 hours.
4. Apply pressure for at least 15 minutes if bleeding occurs.
5. Encourage oral intake of fluids if not contraindicated.
Client and Family Teaching
1. If the abdominal vasculature is to be examined, a cathartic may be administered 1 day before the test and a tap-water enema may be given on the morning of the test.
2. Consume clear liquids only for 24 hours and fast from food and fluids for 8 hours before the test.
3. It is normal to experience a brief flushing sensation and possibly nausea when the dye is injected, but the feeling will pass quickly.
4. It is important to lie still throughout the procedure.
5. Bed rest and frequent site and extremity checks are performed as standard postprocedure care.
6. In women who are breast-feeding, formula should be substituted for breast milk for 1 or more days after the procedure.
Factors That Affect Results
1. Movement of the client during filming may obscure the pictures.
Other Data
1. Clients with cardiomegaly need to be monitored carefully during this procedure or assessed to see if this procedure is fundamentally necessary.
2. Odds of receiving this test are lower for Hispanics when compared to non-Hispanic Caucasian counterparts.
3. See also Cardiac catheterization—Diagnostic ; Cerebral angiogram—Diagnostic ; Pulmonary angiogram—Diagnostic ; or Renal angiogram—Diagnostic .
Arthrography— Diagnostic
Norm.
Intact soft-tissue structures of the joint. Absence of lesions, fractures, or tears.
Usage.
Detection of damage to joint connective tissue and structures (that is, adhesions, tears, fractures). Specific for full-thickness triangular fibrocartilage tears, rotator cuff tears, and ankle ligament visualization. Ganglion cyst.
Description.
Arthrography involves fluoroscopic and radiographic examination of a joint after an injection into the joint of air or radiographic dye. Arthrography provides better visualization of the connective tissue of joints than routine radiography. It is most commonly used to view the knees and shoulders but may also be performed on other joints such as the ankle, hip, wrist, or temporomandibular joint.
Professional Considerations
Consent form IS required.
Risks
Allergic reaction to dye (itching, hives, rash, tight feeling in the throat, shortness of breath, bronchospasm, anaphylaxis, death), renal toxicity; bleeding, hematoma, or infection at injection site.
Contraindications
Previous allergy to iodine, seafood, or radiographic dye; pregnancy; active rheumatoid arthritis; infection of the joint to be studied; pregnancy (if iodinated contract medium is used, because of crossing the blood-placental barrier).
Preparation
1. Obtain a sterile arthrography tray, povidone-iodine solution, and 1% to 2% lidocaine.
2. Have emergency equipment readily available.
3. See Client and Family Teaching .
4. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
Procedure
1. The skin is cleansed with povidone-iodine solution and allowed to dry.
2. A local anesthetic (1%-2% lidocaine) is injected subdermally and subcutaneously around the site to be punctured.
3. A needle is inserted into the joint space, and a small amount of contrast dye is injected through it as placement is checked under fluoroscopy.
4. After correct placement is confirmed, the remainder of the dye is injected and the needle withdrawn.
5. The extremity may be moved briefly through a range of motion, and then several fluoroscopic films are taken of the joint in different positions.
Postprocedure Care
1. Minimize use of the joint for 12 hours.
2. For knee arthrography, an elastic wrap should be worn over the knee for 3-4 days.
Client and Family Teaching
1. Fast from food and fluids for 8 hours before the procedure.
2. Some mild pain and pressure will be felt during the procedure, but local anesthesia will be used to keep these sensations tolerable.
3. Postarthrography edema and tenderness occur frequently for 1-2 days and may be treated with ice packs and mild analgesia. Symptoms lasting more than 2 days necessitate a physician's assessment.
4. If air injection was used, it is normal to feel crepitus in the joint for up to 2 days, because air remains in the joint space until it dissolves into the tissues. The air causes a popping or cracking sensation when the joint moves.
Factors That Affect Results
1. Fluid in the joint space decreases the quality of the films caused by dilution of the dye. If present, it should be aspirated before dye injection.
Other Data
1. Arthrography is 100% specific and 85% sensitive for detection of full-thickness triangular fibrocartilage tears.
2. MRI and arthrography have similar diagnostic values.
Arthropod Identification— Specimen
Norm.
Requires interpretation.
Usage.
Insect bites.
Description.
There are over 1 million species in the phylum Arthropoda, including flies, mosquitos, fleas, lice, itch mites (producing scabies), mites, maggots, bedbugs, spiders, cockroaches, termites, ticks, bees, wasps, and scorpions. Specimens are usually presented for identification after a human has been bitten by or infested with them. Arthropod bites may cause a variety of wheals, rashes, or anaphylactic reactions in humans.
Professional Considerations
Consent form NOT required.
Preparation
1. Obtain alcohol wipes, tweezers, and a container of 70% alcohol.
Procedure
1. Capture and preserve the arthropod in a sealed container of 70% alcohol. If the arthropod is a tick, rub the tick and site with an alcohol wipe. Then, holding the tick close to the skin with tweezers, pull the tick straight out and apply gentle pulling, without twisting, until the tick lets loose from the skin.
2. Wash fly larvae in water and then boil for a few minutes before placing in 70% alcohol.
Postprocedure Care
1. Transport the specimen to the laboratory.
Client and Family Teaching
1. For an arthropod bite or sting, swelling and itching can be controlled by placement of a cold washcloth or towel over the site for 20 minutes once per hour. Change to warm washcloths after 1-2 days.
2. Pain can be reduced by application of a paste of water and baking soda to the site for 5-10 minutes.
3. Itching can be controlled with calamine lotion.
4. Use insect repellent whenever venturing into grassy or wooded areas.
5. The main concern with flea bites is secondary infection. Therefore keep fingernails short to avoid scratching. Bathe in a tub of water filled with 1 kg of starch, apply calamine lotion to skin, and take antihistamines as prescribed. If an infection develops, antibiotics such as neomycin or polymyxin may be prescribed.
6. For head lice:
i. To avoid transmitting head lice:
a. Do not allow your head to come into close proximity with that of another person.
b. During active infestation, rinse hairbrushes and combs off after use, to wash away any lice. Avoid sharing hairbrushes or combs, because they may forcibly remove healthy head lice, which can reinfest for up to 24 hours.
ii. It is not necessary to wash or “disinfest” clothing or linen. This advice is common, but mistaken, and applies only to clothing lice, which are found only on clothes and not on the body. Healthy head lice do not disperse except when scraped off (such as by combing) or when moving directly to another person's head. Shedding on linen occurs only when they are dying.
Factors That Affect Results
1. None.
Other Data
1. Spiders: Two venomous spiders are the brown recluse and the black widow spiders, which are more common in the southern United States. The redleg spider of Florida may also produce symptoms of poisoning. Treatment includes slow intravenous administration of 10 mL of 10% calcium gluconate and a muscle relaxant such as diazepam. A commercially prepared antivenom for the black widow, though rarely needed, is available in vials of 6000 U diluted in 2.5 mL of sterile water and given intramuscularly or intravenously.
2. A generalized systemic reaction to bee, wasp, and ant stings is believed to be IgE mediated. Treatment includes epinephrine hydrochloride 1 : 1000, 0.3-0.5 mL for an adult and 0.01 mL/kg for a child, prednisone orally to reduce swelling, and diphenhydramine hydrochloride, 25-50 mg orally, to relieve itching. “Killer bees” envenomation can cause acute tubular necrosis and death.
3. Lice or itch mites (producing scabies), frequently found in hair on the head or on the hands, feet, and pubic hair, require a thorough application of gamma-benzene hexachloride (Kwell, GBH) cream or lotion. Because GBH is toxic, it is questionable whether it should be used for young children or pregnant women. Some references recommend treatment only if a live louse is found.
4. The puss caterpillar, found in the southeastern United States, especially Texas and Florida, can cause shocklike signs and symptoms, as well as skin necrosis, edematous infiltration, and major fibrinogenolysis. Treatment includes immediate removal of the stinger. This may be followed by slow intravenous administration of 10 mL of 10% calcium gluconate and a muscle relaxant such as diazepam.
5. Mosquitoes are known carriers of yellow fever.
6. Dust mites are retained, thereby increasing allergy symptoms, by larger carpet surfaces, fluorocarbon-treated fibers, and carpets with low pile.
Arthroscopy— Diagnostic
Norm.
Internal anatomy of the joint space is undisturbed. Synovial fluid is clear. Synovial membranes are not erythematous. There are no free-floating materials within the joint space.
Usage.
Diagnostic use of the procedure is mainly to determine the cause of chronic arthritic complaints that cannot be established with serologic tests. The therapeutic use of the procedure involves the treatment of various acute and chronic arthritic conditions (including the management of septic arthritis and the treatment of torn ligaments) that would otherwise require arthrotomy.
Description.
A diagnostic and therapeutic procedure involving the insertion of an arthroscope into a joint that provides direct visualization of the joint space to the physician without the requirement of surgical exposure of the joint (arthrotomy). In addition to the arthroscope, an irrigation cannula and various small resection instruments can be introduced into the joint space during the procedure. Total intravenous anesthesia with propofol and alfentanil or remifentanil does not affect the risk of postoperative nausea and vomiting. Joints that are frequently studied with this procedure include the knee, shoulder, wrist, and (occasionally) the temporomandibular joint. Neurovascular complications are the most serious and devastating complications of this procedure.
Professional Considerations
Consent form IS required.
Risks
Bleeding (hemarthrosis), infection, allergic reaction to the local or general anesthetic agent(s) to be used during the procedure.
Contraindications
History of bleeding diathesis, history of allergic reaction to anesthetic agents to be used during the procedure, severe arthritis resulting in narrowing of the joint space that would preclude insertion of the required instruments, cellulitis over the joint to be studied.
Preparation
1. Preoperative determination of the vital signs is indicated.
2. The surface over the joint to be studied is shaved and prepped with an iodine solution.
3. If the procedure is to be performed with the client under general anesthesia, anesthetic premedication may be given and the client is taken to the operating room where a general anesthetic agent is administered.
4. If the procedure is to be performed with the client under local anesthesia, the client may need to be properly positioned. (As an example, arthroscopy of the knee is at times performed with the client in a sitting position.)
5. Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
Procedure
1. If the procedure is to be performed with the client under local anesthesia, infiltration of the skin over the joint is performed with a local anesthetic agent (lidocaine).
2. The joint space is infiltrated with the local anesthetic agent.
3. If the joint to be studied is located in an extremity, a proximal tourniquet is occasionally applied.
4. A small incision is made, and the irrigation cannula is passed into the joint space. The joint space is irrigated and distended with irrigation solution (saline).
5. The arthroscope is placed into the joint space through a second incision. The internal structures of the joint are visualized.
6. If arthroscopic surgery is to be performed, insertion of various arthroscopic surgical cannulae can be performed through a third incision.
7. At the end of the procedure the instruments are removed from the joint, and the incisions are closed with sutures or Steri-strip tape.
8. Various dressings are applied. In the case of knee arthroscopy, an Ace wrap is often used.
9. The pneumatic cuff is then deflated.
Postprocedure Care
1. Postoperative determination of the vital signs and a dressing check are indicated.
2. Neurovascular assessment of distal extremity for color, temperature, movement and sensation.
3. Frequent reevaluation of the dressing and the joint may be needed. The physician supervising the care of the client should be informed if bleeding, swelling of the joint, or leakage of synovial fluid is noted.
4. Postoperative analgesic medications and antibiotic agents may be ordered by the physician supervising the test.
5. A program of physical therapy may be required, although frequently the client may resume normal activity within 24 hours of the procedure.
Client and Family Teaching
1. A general preoperative orientation to the procedure and postoperative care plan is indicated.
2. The client and family will need instruction in any physical therapy routines or mobility limitations imposed by the procedure.
3. Orientation as to the nature and prognosis of the disease process diagnosed by the arthroscopy may be indicated.
4. An ice pack may help ease postprocedure pain. Use a towel between the ice pack and the joint.
5. Give instructions for crutch walking, including going up and down stairs.
6. Do not exercise the joint more than normal activity for 5-6 weeks after the procedure if surgery was performed.
7. Contact the physician if edema continues more than 3 days or if fever over 101 degrees F (38.3 degrees C) or increased knee pain develops.
Factors That Affect Results
1. Client cooperation during arthroscopy performed with the client under local anesthesia is essential.
2. Severe arthritis-producing deformity of the joint space may limit the effectiveness of the procedure.
3. Postoperative complications such as bleeding or infection may limit the effectiveness of arthroscopic surgical procedures.
Other Data
1. Wrist arthroscopy is ideal for evaluating intra-articular soft tissue injuries.
2. The cause of various types of chronic arthritis can frequently be determined with radiographic or serologic tests without the need to perform arthroscopy.
3. The increasing availability of smaller arthroscopic instruments has resulted in a growing trend to perform these procedures with the client under local anesthesia and in an office (rather than a hospital) setting.
ASA
See Salicylate—Blood .
ASA
See Infertility Screen—Specimen .
Ascorbic Acid
See Vitamin C—Plasma or Serum .
ASC-US
See Pap Smear—Diagnostic .
Ashkenazi Jewish Genetic Carrier Screening Profile
Norm.
Negative.
Usage.
Pre-conception screening for autosomal recessive carrier status.
Description.
Clients whose families have Jewish ancestors from Eastern or Central Europe (Ashkenazi) carry a genetically higher risk for conceiving a child with certain autosomal recessive inherited diseases when both parents carry the abnormal gene. Screening for these abnormal genes associated with Canavan disease, cystic fibrosis, familial dysautonomia, Fanconi anemia, Gaucher disease, Riley-Day syndrome and Tay-Sachs disease may be done as part of genetic counseling prior to conception (Kalman, Wilson, Buller, 2009) .
Professional Considerations
Informed consent is recommended for genetic testing.
Preparation
1. Collect required screening questionnaires regarding client history, including those for cystic fibrosis and Tay-Sachs disease.
2. Tube: Lavender topped EDTA and yellow topped ACD tube.
Procedure
1. Collect 10 ml whole blood.
Postprocedure Care
1. Keep lavender topped tube at room temperature. Refrigerate yellow topped tube.
2. Transport to testing laboratory within 48 hours.
Client and Family Teaching
1. Genetic counseling is recommended. Refer to section in this book on “Informed Consent for Genetic Testing”.
2. If the first person tested is negative for any of the autosomal recessive conditions, testing of the partner is not needed.
3. Rare variants of the diseases may not be identified by this test.
Factors That Affect Results
1. Hemolysis or frozen state of the specimen invalidates results
Other Data
1. Test not indicated for those of non-Ashkenazi ancestry.
2. The Genetic Information Nondiscrimination Act of 2008 prohibits health plans from using genetic family history or genetic test results from influencing eligibility or premiums for health insurance. It also prohibits employers from using this information to influence decisions about hiring, terminating employment, or employment pay, promotions or privileges.
ASM Antibody
See Anti–Smooth Muscle Antibody—Serum .
ASO Titer
See Antistreptolysin-O Titer—Serum .
Aspartate Aminotransferase (AST, Aspartate Transaminase, SGOT)— Serum
Norm.
SI Units
Adult Females
<61 span="" style="white-space: pre;" years=""> 13-45 mU/mL or 8-20 U/L 0.14-0.34 µKat/L10-40 Karmen U/mL 8-20 U/L
>60 years 10-20 U/L 0.17-0.34 µKat/L
Adult Males
<61 span="" style="white-space: pre;" years="">
13-45 mU/mL or 8-20 U/L 0.14-0.34 µKat/L10-40 Karmen U/mL 8-20 U/L
>60 years 11-26 U/L 0.19-0.44 µKat/L
Children
Newborn 25-75 U/L 0.43-1.28 µKat/L
Infants 15-60 U/L 0.26-1.02 µKat/L
2-5 months 20-50 U/L 0.34-0.85 µKat/L
1 year 16-35 U/L 0.27-0.60 µKat/L
5 years 19-28 U/L 0.32-0.48 µKat/L
8-12 years 15-40 U/L 0.26-0.68 µKat/L
12-14 years 15-35 U/L 0.26-0.60 µKat/L
14-16 years 15-30 U/L 0.26-0.51 µKat/L View full size
Increased.
Acute myocardial infarction (increases 6-12 hours after injury, peaks at 18-24 hours, and returns to normal within 1 week; average increases are about 4-fold; large infarcts may cause increases up to 15-fold), alcoholism, anorexia nervosa (emaciated multiorgan disorders), calcium dust inhalation, cerebral infarction, cirrhosis, diabetes mellitus, eating disorders (with liver impacted), hepatitis (viral preicteric phase), HELLP syndrome, intestinal injury, intramuscular injections, irradiation injury, Lassa fever, lead, lipemia, liver disease, liver necrosis post laparoscopic cholecystectomy, metal poisoning, musculoskeletal diseases, myoglobinuria, pancreatitis (acute), polymyositis/dermatomyositis, pulmonary infarction, renal infarction, toxic shock syndrome, trauma. Drugs include allopurinol, aluminum nicotinate, amantadine, ampicillin, anabolic steroids, androgens, ascorbic acid, asparaginase, aspirin (value returns to normal within 48 hours of ingestion), azaserine, baclofen, barbiturates, bethanechol chloride, bromocriptine mesylate, captopril, carbenicillin, carbon tetrachloride, cardiotonic glycosides, carmustine, cephalothin sodium, chlordiazepoxide, chloroquine, chlorpromazine hydrochloride, cholestyramine resin, cholinergics, cinchophen, clindamycin, clofibrate, cloxacillin, codeine, colchicine, cortisone, cyclacillin, cycloserine, desipramine, dicumarol, digitalis, diphenylhydantoin, disopyramide phosphate, erythromycin, ethionamide, ethyl biscoumacetate, floxuridine, flurazepam, flutamide, fosinopril, gentamicin sulfate, griseofulvin, guanethidine analogs, hydralazine, N -hydroxyacetamide, ibufenac, isoniazid, lincomycin, lorazepam, meperidine, methotrexate, methyldopa, metoprolol tartrate, mithramycin, morphine, nafcillin, nalidixic acid, narcotics, niacin, nifedipine, nitrofurantoin, oral contraceptives, oxacillin, para-aminosalicylic acid, phenothiazines, placebo, Polycillin, procainamide hydrochloride, propranolol, propylthiouracil, Prostaphlin, pyrantel pamoate, pyrazinamide, pyridoxine, rifampin, salicylates, statins, sulfamethizole, sulfamethoxypyridazine, tetracycline, theophylline, thiabendazole, thiothixene, thyroid hormone, tolbutamide, tolmetin sodium, troleandomycin, valproic acid, vitamin A, and vitamin B 6 . Herbal or natural remedies include chaparral tea (or misspelled chapparel tea, Larrea tridentata ), Echinacea , pennyroyal. Herbal or natural remedies that have the potential to cause hepatotoxicity and elevate values include akee fruit (ackee, Blighia sapida ), Atractylis gummifera, Azadirachta indica ( Neem tree , margosa ), Berberis vulgaris (barberry), Callilepis laureola (blazing star, Liatris spicata ), chaparral tea ( Larrea tridentata ), cocaine, comfrey (“knitbone,” Symphytum ), Crotalaria (bush tea), cycasin (a toxin from a Cycas species of sago palm of Guam), Echinacea , germander (genera Teucrium and Veronica ; do not confuse with safe skullcap, a name often falsely used in selling germander), Heliotropium (germander, valerian), jin bu huan (‘gold-inconvertible,’ Jin Bu Huan Anodyne Tablets, patent medicine with misidentified constituents: essence of t'ienchi [tianqi] flowers, “Noto-ginseng”; also kombucha; also Lycopodium serratum , or club moss; but with plant alkaloid levo-tetrahydropalmatine, a potent neuroactive substance), ma huang ( Ephedra ), margosa ( Melia azadirachta, Azadirachta indica ), maté tea ( Ilex paraguayensis ), mistletoe, pennyroyal, sassafras, skullcap ( Scutellaria ; do not confuse with unsafe germander), syo-saiko-to (xiao chai hu tang, “minor Bupleurum combination”), Teucrium polium (golden germander), and valerian ( Valeriana officinalis , garden heliotrope).
Decreased.
Beriberi, diabetic ketoacidosis, hemodialysis (chronic), liver disease, and uremia (all conditions cause false decreases). Drugs include metronidazole and trifluoperazine. Herbal or natural remedies include Chinese fructus schizandrae sinensis ( wu wei zi , coffee ( Coffea ) [in alcoholics], “five flavors herb,” Schisandra chinensis [Turcz.] Baill.).
Description.
A catalytic enzyme found primarily in the heart, liver, and muscle tissue. AST is found in two distinct forms or isoenzymes. c-AST is located in cytoplasm, and m-AST is found in mitochondria. Increases in the serum total AST level occur any time there is serious damage to cells. In addition, AST may be found in complex with IgA in hepatic cancer. AST is also evaluated in comparison with alanine aminotransferase (ALT) to serially monitor liver damage.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. Do NOT draw during hemodialysis.
Procedure
1. Draw a 4-mL, nontraumatic blood sample.
Postprocedure Care
1. Handle the specimen carefully, avoiding hemolysis.
Client and Family Teaching
1. Results are normally available within 12 hours.
Factors That Affect Results
1. Hemolysis of specimen and recent IM injections may cause falsely elevated values.
2. Echinacea taken for 8 weeks or longer may cause hepatotoxicity.
Other Data
1. There are no conditions that result in a true decrease in AST. All decreases listed are false decreases.
2. Bloodletting reduces serum aminotransferase in persons with chronic hepatitis C and iron overload.
Aspergillus Antibody
Norm.
Negative <1 8.="" :="" does="" for="" fourfold="" fungi.="" in="" infection:="" not="" opportunistic="" p="" paired="" pathogenesis="" prove="" rise="" serum="" solation="" specimens.="" suspicious="">
Increased.
Allergic bronchopulmonary aspergillosis, hypersensitivity to Aspergillus , immunodeficiency, leukemia, and pulmonary aspergilloma.
Description.
Aspergillus species are saprophytic, opportunistic fungi that can grow on soil and organic materials and often become airborne in large numbers. More than 200 strains exist and may colonize the human body (respiratory tract, skin, nails, ear canal, burns) and become pathogenic when they invade immunosuppressed clients, when they invade human tissue, or when a client becomes sensitized to the organism. In this test, an indirect Coombs' test is performed to identify the presence of Aspergillus antibody.
Professional Considerations
Consent form NOT required.
Preparation
1. Verify whether the client received antifungal skin testing within the last few weeks. Write the dates and names of such tests on the laboratory requisition.
2. Tube: Red topped, red/gray topped, or gold topped.
Procedure
1. Collect a 10-mL blood sample as soon as possible after infection is suspected. Label the specimen as the acute sample.
2. Repeat the test in 2-3 weeks and label the specimen as the convalescent sample.
Postprocedure Care
1. Transport the specimen to the laboratory promptly and refrigerate at 25 degrees C for no longer than 9 hours.
Client and Family Teaching
1. Return in 2-3 weeks for the convalescent sampling.
2. Amphotericin B is used to treat aspergillosis.
Factors That Affect Results
1. False-negative results may occur in immunosuppressed clients.
2. False-positive results may be caused by recent fungal antigen skin tests.
Other Data
1. Five percent of clients without pulmonary aspergillosis or Aspergillus allergy will have Aspergillus antibodies.
2. Identification requires that Aspergillus be directly identified in body tissues or fluids, be isolated in multiple specimens, and be identified by microscopic observation of characteristic conidial formation.
3. The lysis-centrifugation method of culturing is the most sensitive method for detecting molds that cause fungemia. Blood cultures for Aspergillus are helpful in diagnosing an Aspergillus infection only when repeated lysis-centrifugation tests can distinguish between specimen contamination and pathogenesis based on the number of colonies appearing.
4. A biopsy is required to diagnose invasive aspergillosis.
Aspirin
See Salicylate—Blood .
Aspirin Tolerance Test (ASA Tolerance Test, Bleeding Time Aspirin Tolerance Test)— Diagnostic
Norm.
Requires interpretation. Normal baseline Ivy bleeding time is 2-7 minutes. One study demonstrated bleeding time in normal clients to increase from 2.5 to 4.2 minutes at 2 hours after aspirin ingestion. Bleeding time should return to baseline level by 96 hours after aspirin ingestion.
Increased.
Bernard-Soulier syndrome, collagen vascular disease, Cushing's disease, disseminated intravascular coagulation, Glanzmann's thrombasthenia, gray platelet syndrome, hypersplenism, thrombocytopenia with immunosuppression, and von Willebrand's disease. Drugs include anticoagulants (oral), indomethacin, phenylbutazone, and platelet aggregation inhibitor drugs (aspirin, clopidogrel, eptifibatide). Herbs or natural remedies that may inhibit platelet activity include feverfew ( Tanacetum parthenium ), garlic, ginger, Ginkgo biloba , ginseng.
Decreased.
Drugs include 1-deamino-8- d -arginine vasopressin (DDAVP).
Description.
The Ivy bleeding time test is performed before and after aspirin ingestion to evaluate the drug's effect on platelet function. In normal clients, aspirin ingestion has minimal influence on bleeding time.
Professional Considerations
Consent form NOT required for most laboratories.
Risks
Bleeding, ecchymoses, hematoma.
Contraindications
In clients who require upper-extremity restraints, have edematous or very cold arms, or are prone to keloid formation. This test should not be performed if there are contraindications to placing or inflating a blood pressure cuff on the arm (casts, rash, arteriovenous fistula). Other contraindications include platelet count <50 3="" 5="" acetyl="" as="" aspirin="" bleeding="" changes="" containing="" days.="" diseases="" disorders="" groups="" infectious="" medications="" mm="" or="" p="" previous="" senile="" severe="" skin="" such="" the="" those="" within="">
Preparation
1. See Client and Family Teaching .
2. Obtain povidone-iodine solution, a blood pressure cuff, a lancet, a stopwatch, and filter paper.
Procedure
1. Cleanse the volar aspect of the forearm with povidone-iodine and allow it to dry completely.
2. Place the blood pressure cuff on the upper arm and inflate to 40 mm Hg.
3. Make two small incisions 2-3 mm deep on the prepared site. Start timing with the stopwatch.
4. Remove blood from the wound with filter paper every 15 seconds until bleeding stops. Stop timing with the stopwatch.
5. If bleeding time is more than 10 minutes, do not proceed further because this test would be contraindicated.
6. Administer 10 grains (adults) or 5 grains (children weighing less than 32 kg) of aspirin orally.
7. Repeat steps 1 through 5 after 2 hours.
Postprocedure Care
1. If bleeding time is normal, apply a Band-Aid to the site. If bleeding time is prolonged, apply a pressure bandage to the site.
2. Assess the site(s) for bleeding every 5 minutes for hour. Observe for signs of site infection until healed.
Client and Family Teaching
1. Do not take aspirin for 5 days before this test.
2. Bring reading material or some other diversion because the test takes 2-3 hours.
Factors That Affect Results
1. The most sensitive and reproducible measurements may be those taken from a horizontal incision.
Other Data
1. The depth of the puncture with the lancet is difficult to standardize and results in poorly reproducible bleeding times.
AST
See Aspartate Aminotransferase—Serum .
AT-III Test
See Antithrombin III Test—Diagnostic .
Atrial Natriuretic Hormone
See Natriuretic Peptides—Plasma .
Atrial Natriuretic Peptide
See Natriuretic Peptides—Plasma .
Audiometry Test (Pure Tone Audiometry and Speech Audiometry, Vestibular Evoked Myogenic Potential)— Diagnostic
Norm.
Adult 0-25 dB HL hearing sensitivity
Child 0-15 dB HL hearing sensitivity
Word-discrimination score Client is able to repeat list of spoken words with 90% accuracy
VEMP Positive steady results View full size
Usage.
Delineation of type and amount of hearing loss (that is, conductive, sensorineural, or mixed), rehabilitation monitoring post cochlear implant or post stapedectomy, diagnosis of glue ear (otitis media with effusion). Vestibular evoked myogenic potential (VEMP) is used to help evaluate clients experiencing symptoms of dizziness and/or suspected of having vestibulocochlear disorders, as well as to help differentiate sudden deafness from the beginning stage of Ménière's disease. Higher peak amplitudes (VEMP) are seen in clients with endolymphatic hydrops or multiple sclerosis and in clients with distended saccular hydrops seen in the early stage of Ménière's disease.
Description.
Pure tone audiometry is a hearing test using an audiometer that sends tones into the client's ear and vibrations through the bone. It measures the frequencies at which the client is able to hear 50% or more of the tones. The test is able to detect defects in air conduction (conductive hearing loss) through the use of tones or defects in air and bone conduction (sensorineural hearing loss) through the use of vibrations to help identify the amount and type of hearing loss present. Speech audiometry is a hearing test that determines the client's speech-reception threshold and word-discrimination score by measuring the number of words the client can repeat after they are heard when delivered through earphones at precise decibel intensities. Speech audiometry helps differentiate between conductive and sensorineural hearing loss. Vestibular evoked myogenic potential is a reflex conducted via the inferior vestibular nerve that indicates the integrity of the vestibular response. Measurement is performed via skull taps with recording of resultant muscular responses.
Professional Considerations
Consent form NOT required.
Preparation
1. See Client and Family Teaching .
2. Ensure that the external auditory canal is free of impacted cerumen.
3. Obtain an audiometer, earphones, a vibrator for bone-conduction testing, and an otoscope.
Procedure
1. A plastic tube may be inserted into the external auditory canal to maintain the canal's patency during testing with earphones.
2. The earphones are placed over the ears and fastened in place.
3. A preliminary tone is demonstrated for the client to become familiar with the test.
4. The ear not being tested is masked with audiometer noise to prevent crossover interference and subsequent inaccurate estimation of hearing loss.
5. Air conduction testing : The better ear is tested first. The client is instructed to give a signal each time a tone is heard. Starting with 1000 Hz, tones are delivered to the ear, decreasing by increments of 10 dB until a negative response is obtained. Tone levels are then increased in smaller increments and then decreased until the air conduction threshold level is obtained. The air conduction threshold level is the lowest hertz level at which the client is able to hear two out of three tones. This procedure is then repeated several times, starting with a different tone level each time (such as 2000, 4000, 8000, 1000, 500, and finally 250 Hz). The second ear is then tested in the same way. Finally, retesting is performed on each ear to determine test/retest reliability. Acceptable variation for retesting for each ear must be within 5 dB above or below the initial test result. Graphic recordings are made of the threshold levels.
6. Bone conduction testing : The better ear is tested first. After removal of the earphones, the bone conduction vibrator is held on the mastoid process of the ear. Starting from 250 Hz, tones are delivered to the ear, with decrements at 10 dB until a negative response is obtained. Tone levels are then increased in smaller increments and then decreased until the bone conduction threshold level is obtained. The bone conduction threshold level is the lowest hertz level at which the client is able to hear two out of three tones. This procedure is then repeated several times, starting with a different tone level each time (500, 1000, 2000, and finally 4000 Hz). The second ear is then tested in the same way. Finally, retesting is performed on each ear to determine test/retest reliability. Acceptable variation for retesting for each ear must be within 5 dB above or below the initial test result. Graphic recordings are made of the threshold levels.
7. Speech reception threshold measurement : Two-syllable, familiar, spoken words are delivered through the earphones. The client is asked to repeat each word. The speech reception threshold is the decibel level at which the client is able to restate correctly at least half the words.
8. Word discrimination score : One-syllable, familiar, phonetically balanced words are delivered through the earphones at 30 dB higher than the client's own speech reception threshold. The client is asked to repeat each word. Clients with conductive hearing loss will have a normal word discrimination score. Those with sensorineural hearing loss will have a lower than normal score.
9. Amount-of-hearing-loss calculation: The amount of hearing loss, called the “pure tone average” (PTA), is calculated by averaging the air conduction threshold levels. Mild hearing loss demonstrates a PTA of 26-40 dB. Moderate hearing loss demonstrates a PTA of 41-55 dB. Moderately severe hearing loss demonstrates a PTA of 56-70 dB. Severe hearing loss demonstrates a PTA of 71-90 dB. Profound hearing loss demonstrates a PTA of >90 dB.
10. Type-of-hearing-loss calculation: The type of hearing loss is interpreted by examination of the relationship between the air conduction threshold levels and the bone conduction threshold levels at the different frequencies. In sensorineural hearing loss, both thresholds are depressed to about the same degree. In conductive hearing loss, only the air conduction thresholds are depressed. In mixed hearing loss, both thresholds are depressed, but air conduction threshold levels are more depressed than bone conduction threshold levels.
11. Vestibular evoked myogenic potential : Skin electrodes are placed over both sternocleidomastoid muscles. Light skull taps over each ear and on the middle of the forehead are manually applied. Alternatively, loud clicks are produced externally to each ear. The responses evoked by these taps that travel through the sternocleidomastoid muscles are measured through the electrodes and recorded as waveforms.
Postprocedure Care
1. Cleanse the earphones and otoscope with antiseptic.
Client and Family Teaching
1. Stay in an environment free of extremely loud noises for 16 hours before the test.
Factors That Affect Results
1. Testing should be performed in a very quiet environment for the most accurate results.
2. The client should not be able to see the examiner because changes in tone level are made. Signals should be delivered in a nonrhythmic pattern.
3. The client must be able to distinguish between the pure tones and tinnitus or vibrotactile stimulation.
4. Test/retest differences of more than 10 dB may be caused by unreliable equipment.
5. The use of plastic tubes to maintain external auditory canal patency should be noted on the audiogram.
6. Low levels of serum estradiol can impede hearing sensitivity in pure tone audiometry results in postmenopausal women.
Other Data
1. See also Acoustic immittance tests—Diagnostic .
2. There is higher prevalence of age-related hearing impairment in persons with high body mass index, history of high triglyceride levels, and history of smoking. Therefore efforts directed toward modifiable risk factors for cardiovascular disease could also impact or slow the development of age-related hearing loss.
Automated Reagin Testing (ART)— Diagnostic
Norm.
Negative.
Titer Interpretation
Nonreactive Negative
≤ 1 : 8 False positive
1 : 9 to 1 : 32 Primary-stage syphilis (requiring interpretation)
>1 : 32 Secondary-stage syphilis View full size
Positive.
Syphilis. (See Factors That Affect Results for biologic false-positive results.)
Description.
A nonspecific, nontreponemal test used for syphilis screening and monitoring of response to therapy in the post chancre period of the primary stage and in the secondary stage when treponemal antibodies are more difficult to detect. When Treponema pallidum , the causative agent of syphilis, invades human tissue, reagin is produced and can be isolated from 7 to 21 days after the appearance of the chancre. Results are reported as the highest titer that produces a positive reaction.
Professional Considerations
Consent form NOT required.
Preparation
1. Tube: Red topped, red/gray topped, or gold topped.
2. See Client and Family Teaching .
Procedure
1. Draw a 5-mL blood sample.
Postprocedure Care
1. None.
Client and Family Teaching
1. Do not drink alcohol for 24 hours before testing.
2. Weekly testing for 2 months is recommended before syphilis can be ruled out.
3. If testing positive:
i. Notify all sexual contacts from the last 90 days (if early stage) to be tested for syphilis.
ii. Syphilis can be cured with antibiotics. These may worsen the symptoms for the first 24 hours.
iii. Do not have sex for 2 months and until after repeat testing has confirmed that the syphilis is cured. Use condoms after that for 2 years. Return for repeat testing every 3-4 months for the next 2 years to make sure the disease is cured.
iv. Do not become pregnant for 2 years because syphilis can be transmitted to the fetus.
v. If left untreated, syphilis can damage many body organs, including the brain, over several years.
Factors That Affect Results
1. Reject hemolyzed specimens.
2. False-negative results may occur before the appearance of the chancre in the initial stage of syphilis or during the tertiary stage.
3. False-negative results may be caused by ingestion of alcohol within 24 hours before specimen collection.
4. Biologic false-positive results lasting up to 6 months may be caused by bejel, chickenpox, DPT immunization, hepatitis (infectious), malaria, measles, mononucleosis (infectious), pneumonia (atypical, pneumococcal), scarlet fever, smallpox vaccination, subacute bacterial endocarditis, or tuberculosis.
5. Biologic false-positive results lasting more than 6 months may be caused by hyperglobulinemia, leprosy, leptospirosis, periarteritis nodosa, pinta, rheumatic fever, rheumatoid arthritis, systemic lupus erythematosus, thyroiditis, Vaccinia , or yaws.
Other Data
1. Suspected false-positive results should be followed by repeat testing at 3, 6, and 9 months.
Autoprothrombin IIA
See Protein C—Blood .
Autopsy— Diagnostic
Norm.
Requires interpretation.
Usage.
Determination of cause and manner of death, reporting of contagious diseases, quality assurance, teaching, and legal purposes.
Description.
A postmortem examination and dissection of a corpse. The procedure is usually performed by two pathologists and an assistant.
Professional Considerations
Consent form IS required.
Preparation
1. After death, determination should be made whether the circumstances of death require that the coroner be notified. Coroner's cases usually include unexpected death, death within 24 hours of admission to a hospital, death while under anesthesia, suspected homicides or suicides, accidental or violent deaths, deaths of clients with contagious disease, or any death occurring under unusual circumstances or involving the public interest. If any of these conditions apply, the coroner should be called by the physician for a determination of the need for an autopsy. If the coroner determines that an autopsy is required, the family should be notified, but next-of-kin permission is not needed.
2. Autopsy may also be performed without next-of-kin permission when it is necessary to complete the death certificate or when the deceased client has given consent before death.
3. When the need for an autopsy is determined, other than for coroner's cases, next-of-kin permission must be obtained by means of a signature on the consent form or possibly by a witnessed telephone conversation between the physician and the next of kin. Guidelines vary depending on area laws and institution.
4. All invasive lines, tubes, and devices should be left intact in the body.
5. Obtain an autopsy knife with a blade, a scalpel with a disposable blade, toothed forceps, forceps with serrated tips, a medium-long knife with a blade, a long knife with a blade, scissors with one pointed and one blunt blade, scissors with two blunt blades, scissors for cutting bones, intestinal scissors (enterotome), scissors with long curved blades, a 1-mm probe, a metal metric rule, a costotome, rib shears, intestinal clamps, a vibratory saw with large blades, an amputating saw, a band saw, a hammer with a hook, a chisel, bone-cutting forceps, a meter stick, a body scale, an organ scale, balances, a ladle, a graduate, sea sponges, pans with fixative, pan and pail containers, a large container for fixation of gross organs in solution, fixing solution, string, needles, abrasive whetstone and oil, and a slicing machine.
6. Obtain containers for the samples for toxicologic studies, culture, or cytologic tests.
7. Make sure that the autopsy-permit name and identification number correspond to the name and identification number on the client's body. If there are no tags on the body, have the nurse, physician, or relative identify the body.
8. Wear a mask, an eye or face shield, gloves, and a plastic apron.
Procedure
1. Recording : The sequence of events and findings of autopsy are recorded either by concurrently written notes or by a foot-operated dictation machine. Descriptions of the body and organs, including condition, arrangement, and weight of the organs, are made and recorded as the dissection is performed.
2. Sequence : The sequence of the autopsy may vary. In cases in which a specific cause of death is suspected, the appropriate body cavity for that cause may be opened first. A usual autopsy proceeds in the following order: external examination; incision of the skin, ribs, and sternoclavicular joints; examination of thoracic and abdominal cavities; removal and examination of the organs of the trunk (thymus, heart, lungs, mediastinal lymph nodes, spleen, intestines, diaphragm, liver, gallbladder, pancreas, stomach, duodenum, rectum, spermatic cords, testes, adrenals, uterus, ovarian tubes, ovaries, bone marrow [sternal, vertebral, femoral], neck organs, bones, joints, and muscles); and removal and examination of the organs of the cranium and spine (brain, eyes, ears, paranasal sinuses, pituitary gland, spinal cord, and spinal root ganglia).
3. Content of assessment : In the external examination, the body is observed and palpated, and the length, size, and weight are measured. Rigor mortis, edema, and jaundice are noted. The head, lymph nodes, and genitalia are assessed. A Y incision is then made on the torso, and the thoracic and abdominal cavities are assessed. The arrangement and status of the organs and the presence of adhesions, excess fluid, or gas are noted. As they are excised, the weight, size, and contents of the organs and blood vessels are assessed. Biopsy specimens, sections, and smears may be taken throughout the process. The organs of the cranium and spine are then assessed. An incision is made from ear to ear over the vertex of the cranium, and the scalp is separated from the skull with a scalpel. The anterior portion of the scalp is pulled down over the forehead and face. After the skull is opened with a saw and the top portion removed, the brain is removed and placed in 10% formalin. Biopsy specimens of the brain are taken if a virus is suspected. The remainder of the head organs are removed and examined. Formalin is injected into the eyes before removal. The spinal cord is then removed and examined for lesions. Complete organs or portions of organs may be fixed in solution for later reference. An alternative method is to remove the trunk organs in one block, with examination of organs on a dissecting table.
Postprocedure Care
1. The body is cleansed, and the incisions are sewn. The body may or may not be embalmed at this point.
Client and Family Teaching
1. Autopsy incisions will not be visible should an open-casket wake be held.
2. Durable Power of Attorney for Health Care does NOT apply after death.
Factors That Affect Results
1. A routine hospital autopsy should be interrupted and the coroner notified if any unexpected findings that may be of traumatic origin are encountered.
Other Data
1. The order of authority for granting permission for an autopsy is normally spouse, adult child, parent, adult sibling, other relative, and any other person accepting responsibility for burial of the body. This order may vary by area laws.
2. Be aware of religious considerations concerning autopsy.
3. There is a 44% discordance rate between clinical and autopsy diagnosis of malignant neoplasms.
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