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A1C test
HbA1C test; Glycated hemoglobin test; Glycohemoglobin test; Hemoglobin A1C; Diabetes - A1C; Diabetic - A1C
A1C is a lab test that shows the average level of blood sugar (glucose) over the previous 3 months. It shows how well you are controlling your diabetes.
How the Test is Performed
A blood sample is needed. Two methods are available:
- Blood drawn from a vein. This is done at a lab.
- Finger stick. This can be done in your health care provider's office. Or you may be prescribed a kit that you can use at home.
How to Prepare for the Test
No special preparation is needed. The food you have recently eaten does not affect the A1C test, so you do not need to fast to prepare for this blood test.
How the Test will Feel
With a finger stick, you may feel slight pain.
With blood drawn from a vein, you may feel a slight pinch or some stinging when the needle is inserted. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
Your provider may order this test if you have diabetes . It shows how well you are controlling your diabetes.
Diabetes
Diabetes is a chronic disease in which the body cannot regulate the amount of sugar in the blood.
The test may also be used to screen for diabetes.
Ask your provider how often you should have your A1C level tested. Usually, testing every 3 or 6 months is recommended.
Normal Results
The following are the results when A1C is being used to diagnose diabetes:
- Normal (no diabetes): Less than 5.7%
- Pre-diabetes: 5.7% to 6.4%
- Diabetes: 6.5% or higher
If you have diabetes, you and your provider will discuss the correct range for you. For many people, the goal is to keep the level below 7%.
The test result may be incorrect in people with anemia, kidney disease, or certain blood disorders ( thalassemia ). Talk to your provider if you have any of these conditions. Certain medicines can also result in a false A1C level.
Thalassemia
Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin. Hemoglobin is the p...
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
An abnormal result means that you have had a high blood sugar level over a period of weeks to months.
If your A1C is above 6.5% and you do not already have diabetes, you may be diagnosed with diabetes.
If your level is above 7% and you have diabetes, it often means that your blood sugar is not well controlled. You and your provider should determine your target A1C.
The higher your A1C, the higher the risk that you will develop problems such as:
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Eye disease
Eye disease
Diabetes can harm the eyes. It can damage the small blood vessels in the retina, the back part of your eye. This condition is called diabetic retin...
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Kidney disease
Kidney disease
Kidney disease or kidney damage often occurs over time in people with diabetes. This type of kidney disease is called diabetic nephropathy.
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Nerve damage
Nerve damage
Nerve damage that occurs in people with diabetes is called diabetic neuropathy. This condition is a complication of diabetes.
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If your A1C stays high, talk to your provider about how to best manage your blood sugar .
How to best manage your blood sugar
Hyperglycemia - control; Hypoglycemia - control; Diabetes - blood sugar control; Blood glucose - managing
Risks
Obtaining a blood sample from some people may be more difficult than from others.
Other risks of having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
American Diabetes Association. Standards of medical care in diabetes-2016: summary of revisions 5. Glycemic targets. Diabetes Care . 2016:39;Suppl 1:S39-S46. PMID: 26696680. www.ncbi.nlm.nih.gov/pubmed/26696680 .
Chernecky CC, Berger BJ. Glycosylated hemoglobin (GHb, glycohemoglobin, glycated hemoglobin, HbA1a, HbA1b, HbA1c - blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. Philadelphia, PA: Elsevier; 2013:596-597.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 5/2/2016
Reviewed By: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
