The glycolated hemoglobin test (A1c, also called hemoglobin A1c or the glycosylated hemoglobin test) is an important blood test to diagnose diabetes or determine control of your diabetes. It provides an average blood glucose measurement over the past six to twelve weeks and is used in conjunction with home glucose monitoring to make treatment adjustments.
The normal range for the A1c test is between 4% and 6% for people without diabetes. The ideal range for people with diabetes is generally less than 7%. For diagnostic purposes, two separate A1c tests at 6.5% are positive for diabetes.
People with diabetes who are treated with insulin should have this test four times a year (every 3 months).
The test may be needed more frequently when your diabetes is not well-controlled. However, the test should be performed no more often than every six weeks. Those who are not treated with insulin should have this test every 4 to 6 months.