Quick HbA1c Facts

What is it and Why is is Important

Blood Sugar Test
A blood sugar testing device.. Alden Chadwick/Moment/Getty Images

If you have diabetes, regardless of the type, no doubt the terms hemoglobin A1c, HbA1c or A1c have become a part of your vocabulary. If you don't have diabetes, you are likely to run into the term in your medical record as it is used as a screening test for metabolic syndrome and diabetes, especially if you have a high blood glucose on a checkup. It is an important and common topic of conversation for people with diabetes.

What is HbA1c?

  • HbA1c stands for glycated hemoglobin or glycosylated hemoglobin.
  • Hemoglobin is a protein in red blood cells. It is what carries oxygen throughout your body. Hemoglobin contains iron and it's what gives your blood the red color.
  • Glucose molecules stick to hemoglobin.
  • "Glycated" or "glycosylated" refers to when glucose sticks to the hemoglobin protein.

Why HbA1c is Important for Diabetes Monitoring

  • The HbA1c test gives an idea of your average blood sugar levels over the past two to three months.
  • Results indicate how changes in your regimen have affected your control.
  • If necessary, your doctor will use the results to modify your medications, diet and exercise.
  • Good control reduces the risk for vascular complications occurring in your eyes, kidneys, heart, nerves, digestive system, circulatory system and sexual organs.

The HbA1c Test

  • Test results indicate what percentage of your hemoglobin proteins are "glycated" or have glucose stuck to them. If you have a 6% HbA1c test result, this means that 6% of your hemoglobin proteins were glycated.
  • Results may also be provided in an eAG measurement (see below).
  • The test can be performed at your doctor's office or sent to a laboratory. If you have diabetes, you can also use an at-home test, but this is not recommended for screening people who haven't been diagnosed.
  • The result is an average and a patient may have a "good" result even if they have had extreme high and low glucose levels, so regular self-monitoring is still important.

    HbA1c Normal Levels

    • The normal level for a person without diabetes is about 5%.
    • The American College of Endocrinology and The International Diabetes Federation recommend levels under 6.5% for people with diabetes.
    • The American Diabetes Association recommends levels under 7% for most people with diabetes. Your doctor may recommend different levels for you based on your individual situation.

    How Often Should the HbA1c Test be Performed?

    • The test is usually recommended every three months.
    • If levels are good and stable, twice a year may be sufficient.

    What is Estimated Average Glucose (eAG)?

    • HbA1c results can also be expressed in eAG units.
    • The term eAG is recommended by the American Diabetes Association as another way to express HbA1c results so that health care providers can provide results to patients in the same units used for self-monitoring at home.
    • Look at our A1c and eAG Conversion Chart to see how the HbA1c results translate into numbers you may be more familiar with at home.
    • In a nutshell, if you have an hbA1c result of 6%, then this means your average glucose levels for the past 2-3 months have been approximately 126 mg/dl. This is pretty close to the type of result you would obtain on your home glucometer.


      A1C. American Diabetes Association. Accessed: April 20, 2011.

      A1c and the eAG. Lab Tests Online. Accessed: April 20, 2011.

      If You Have Diabetes, Know Your Blood Sugar Numbers! National Diabetes Education Program. National Institute of Health. Accessed: April 20, 2011.

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