The HbA1c or the diagnosis of diabetes: • assay

Recommendation of the International Expert
Committee
For the diagnosis of diabetes:
• The HbA1c assay is an accurate, precise measure of chronic
glycaemic levels and correlates well with the risk of diabetes
complications.
• The HbA1c assay has several advantages over laboratory
measures of glucose.
• Diabetes should be diagnosed when HbA1c is ≥6.5%. Diagnosis
should be confirmed with a repeat HbA1c test. Confirmation is
not required in symptomatic subjects with plasma glucose levels
≥11.1 mmol/l.
• If HbA1c testing is not possible, previously recommended
diagnostic methods (e.g. FPG or 2 hour OGTT, with
confirmation) are acceptable.
• HbA1c testing is indicated in children in whom diabetes is
suspected but the classic symptoms and a casual plasma glucose
≥11.1 mmol/l are not found.
For the identification of those at high risk for diabetes:
• The risk for diabetes based on levels of glycemia is a continuum;
therefore, there is no lower glycemic threshold at which risk
clearly begins.
• The categorical clinical states pre-diabetes, IFG, and IGT fail to
capture the continuum of risk and will be phased out of use as
HbA1c measurements replace glucose measurements.
• Those with HbA1c levels below the threshold for diabetes but
≥6.0% should receive demonstrably effective preventive
interventions. Those with HbA1c below this range may still be at
risk and, depending on the presence of other diabetes risk
factors, may also benefit from prevention efforts.
(Adapted from: The International Expert Committee. International
Expert Committee Report on the role of the HbA1c assay in the
diagnosis of diabetes. Diabetes Care 2009;32:1327–34; 2009)