Interpretations

'When diagnosing diabetes, an abnormal test result should be confirmed with repeat testing except in individuals with classic symptoms of hyperglycemia or hyperglycemic crisis and a random plasma glucose ≥200 mg/dL. The HbA1c test should be performed using an NGSP certified method and standardized or traceable to the (DCCT) reference assay. The American Diabetes Association (ADA) recommends HbA1c be measured 3-4 times per year for type 1 diabetics or poorly controlled type 2 diabetics, and 2 times per year for well-controlled type 2 diabetics.

HbA1c reflects the average blood glucose levels over the preceding 3 months (the average life of a red blood cell) and therefore may be falsely low during pregnancy or any other condition associated with recent onset of hyperglycemia. HbA1c should not be used to diagnose diabetes during pregnancy or to diagnose gestational diabetes. HbA1c must not be used for the diagnosis of diabetes mellitus in patients with Hb variants such as HbSS, HbCC or HbSC. In such situations, fructosamine should be used as an alternate method for monitoring glycemic control. HbA1c should not be used to diagnose or monitor diabetes in patients with any conditions resulting in decreased erythrocyte survival, decrease in mean erythrocyte age or abnormal red blood cell turnover (e.g. hemolytic anemia, including hereditary spherocytosis, iron deficiency, thalassemias, malignancies, recovery from acute blood loss and severe chronic hepatic and renal disease). Shortened red cell survival time will reduce the exposure of red cells to glucose, with a resultant decrease in HbA1c values.

This HbA1c assay should not replace glucose testing in newborn or pediatric patients. Specimens containing high amounts of HbF (>7%) may result in lower than expected HbA1c results. HbA1c results are invalid for patients with abnormal amounts of HbF including those with known Hereditary Persistence of Fetal Hemoglobin.'