HbA1c: review and recent developments Lowering of blood sugar in diabetic patients reduces the risk of macrovascular and especially microvascular complications. Testing for HbA1c is a simple way to obtain an estimation of the average blood sugar during the past two months. Through the level of HbA1c, patients and doctors can check the control of blood sugar and set therapeutic goals (with blood glucose self monitoring as needed). HbA1c dosage should be performed with a certified method under quality control. Results should be traceable to the DCCT and UKPDS method. One should keep in mind the different factors other than blood sugar that can interfere with HbA1c testing and alter the results such as abnormal variants of haemoglobin, blood loss, haemolysis and analytical variability.