Glycosylated Hemoglobin Test
(HbA1c; GHb; Glycohemoglobin; Diabetic Control Index)
A glycosylated hemoglobin test (HbA1c) is a blood test that measures the amount of glycosylated hemoglobin in the blood. Hemoglobin is a protein found in the blood. Glycosylated hemoglobin means that glucose (sugar) has attached to the hemoglobin protein. The higher your blood sugar is, the more that glucose gets attached to your hemoglobin.
Reasons for Test
HbA1c shows how high your blood sugar levels have been during the past three months. This can help your doctor determine how well you are controlling your diabetes. Your doctor may also use HbA1c to test you for diabetes.
What to Expect
Description of Test
You will roll up your sleeve. An elastic band will be wrapped around your upper arm. An area on your arm will be cleaned with alcohol. The needle will then be inserted into your arm. A small amount of blood will be drawn into a tube. The needle will be removed. Pressure will be applied to the puncture site. A small bandage may be placed on the site. Your blood will be sent to a lab for testing.
Apply pressure to the site until bleeding stops.
How Long Will It Take?
Less than five minutes
Will It Hurt?
It may hurt slightly when the needle is inserted.
Talk to your doctor about what goal is right for you. If your HbA1c levels are high, you may need a change in treatment, such as:
- Changing your medicines
- Increasing your level of physical activity
- Modifying your diet
Talk with your doctor about when you should be tested again.
American Diabetes Association
National Diabetes Education Program
Canadian Diabetes Association
American Diabetes Association. Standards of medical care in diabetes—2008. Diabetes Care. 2008;31:S12-S54.
Aronow WS, Ahn C, Weiss MB, Babu S. Relation of increased hemoglobin A1c levels to severity of peripheral arterial disease in patients with diabetes mellitus. Am J Cardiol. 2007;99:1468-1469.
Check your hemoglobin A1c IQ. National Diabetes Education Program website. Available at: http://ndep.nih.gov/materials/pubs/HbA1c/HbA1c-checkIQ.htm. Accessed April 1, 2003.
Glycosylated hemoglobin. National Library of Medicine, Medline Plus website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/003640.htm. Updated May 2009. Accessed September 30, 2009.
A new number. American Diabetes Association website. Available at: http://forecast.diabetes.org/magazine/features/new-number. Accessed September 30, 2009.
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Standards of medical care in diabetes mellitus. American Diabetes Association website. Available at: http://care.diabetesjournals.org/content/26/suppl_1/s33.full. Accessed September 30, 2009.
Why is interpreting HbA1c values tricky? Internet FAQ Consortium website. Available at: http://www.faqs.org/faqs/diabetes/faq/part2/preamble.html. Accessed April 13, 2003.
Last reviewed October 2009 by
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