HbA1c as a diagnostic tool in diabetes mellitus

Hemoglobin A1c (HbA1c) expresses the ratio between glycated HbA1 and total HbA1 and reflects the average plasma glucose concentration the preceding 2-3 months. It has become the most important marker of chronic hyperglycemia and is closely correlated to late complications of diabetes. The analysis has now been standardized and traceable to an international reference material and reference methods. Standardization of the HbA1c analyses paved the way for it to become the primary tool for diagnosing diabetes. Despite some limitations in which HbA1c is not representative of average glucose concentration, the inclusion of HbA1c as a diagnostic tool will simplify the diagnostics of diabetes compared with the glucose criteria, and hopefully improve the prevention of late complications of diabetes.