HbA1c — An analyte of increasing importance

Since the incorporation in 1976 of HbA1c into a monitoring program of individuals with diabetes, this test has become the gold standard for assessment of glycemic control.Analytical methods have steadily improved in the past two decades, largely through the efforts of the National Glycohemoglobin Standardization program (NGSP). The new definition of HbA1c and the introduction of an analytically pure calibrator have increased the possibility for greater improvements in analytical performance. Controversies exist in the reporting of HbA1c. The use of HbA1c has expanded beyond the use solely as a measure of glycemic control into a test for screening and diagnosing diabetes. With improvements in analytical performance, the effects of demographic factors such as age and ethnicity and clinical factors such as iron deficiency have been observed.In this review, the history, formation, analytical methods and parameters that affect HbA1c analysis are discussed.

► Review of the history and current uses of HbA1c.
► Review of the analytical challenges of this assay and recommendations to deal with these challenges.
► Review of the analytical, clinical and demographic factors that effect HbA1c results.