• Definition

    HbA1c is a test that measures the amount of glycated hemoglobin in your blood. Your doctor may order this test if you have diabetes.

    Alternative Names

    Glycated hemoglobin; Glycosylated hemoglobin; Hemoglobin - glycosylated; A1C; GHb; Glycohemoglobin; Diabetic control index

    How the test is performed

    Blood is drawn from a vein. The vein is usually on the inside of your elbow or the back of your hand. A nurse will clean the site for germs. The nurse then wraps an elastic band around the upper arm. This puts pressure on the area and makes the vein swell with blood.

    Next, the needle is gently inserted into your vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed. Then the area is covered to stop any bleeding.

    In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

    How to prepare for the test

    No special preparation is needed.

    How the test will feel

    When the needle is inserted, you may feel a slight pinch or some stinging. Afterward, there may be some throbbing.

    Why the test is performed

    Your doctor may order this test if you have diabetes. It is used to measure your blood sugar control over several months. It can give a good estimate of how well you have managed your diabetes.

    The test may also be used to screen for diabetes.

    You have more glycated hemoglobin if you have had high levels of sugar in your blood. In general, the higher your test result is, the higher the risk that you will develop problems. You could develop eye or heart disease. Uncontrolled diabetes can also lead to kidney disease, nerve damage, or stroke.

    This is especially true if your HbA1c remains high for a long time.

    The closer your level is to normal, the less risk you have for these problems.