Glycated haemoglobin (HbA_1c) monitoring

This article describes two common scenarios involving the use of glycated haemoglobin (HbA_1c) that may be seen in primary care and considers their potential clinical implications in monitoring patients with diabetes.

HbA_1c has become established as the monitoring test of choice to assess medium term diabetic control and as a key parameter on which to base changes in management of patients. Common situations exist, however, in which the HbA_1c can be misleading. As the average lifespan of a red blood cell is approximately 120 days, in situations in which red cell lifespan is reduced HbA_1c may not accurately reflect diabetic control. With increasing emphasis on achieving lower HbA_1c values in patients with diabetes, clinicians need to be aware of these situations and understand the limitations of the test methods used.