The A1c test is used primarily to monitor the
glucose control of diabetics over time. Depending on the type of
diabetes that you have, how well your diabetes is controlled, and your doctor, your A1c may be measured 2 to 4 times each year. A 1% change in an A1c result reflects a change of about 30 mg/dL in average blood glucose. For instance, an A1c of 6% corresponds to an average glucose of 135 mg/dL, while an A1c of 9% corresponds to an average glucose of 240 mg/dL.