A1C is a blood test that measures your average blood sugar levels over the past two to three months. It does this by checking how much glucose (sugar) has attached to hemoglobin, the protein in ...

For example, an average blood glucose of 154 mg/dL translates into an A1C of about 7%. This is above normal, given that a diagnosis of diabetes is usually given when fasting blood sugar levels ...

C. Ronald Kahn, M.D. President and Director, Joslin Diabetes Center What is the A1c blood test? The hemoglobin A1C test is a measure of what we call long term glucose control. The way this works ...