The A1C test is a blood test that provides information about a person’s average levels of blood glucose, also called blood sugar, over the past 3 months. The A1C test is sometimes called the hemoglobin A1c, HbA1c, or glycohemoglobin test.

You and your health care team should discuss the A1C goal that is right for you.

An A1C of 6 or less usually represents normal (healthy) blood sugar control.

For most people with diabetes, the A1C goal is less than 7. An A1C higher than 7 means that you have a greater chance of eye disease (diabetic retinopathy), kidney disease, or nerve damage (diabetic neuropathy). Lowering your A1C by any amount can improve your chances of staying healthy. If your number is 7 or more, or above your goal, ask your health care team about changing your treatment plan to bring your A1C number down.

The following list provides the percentages that indicate diagnoses of normal, diabetes, and prediabetes according to A1C levels.

  • Normal: A1C level below 5.7%
  • Diabetes: A1C level 6.5% or above
  • Prediabetes: A1C level 5.7% to 6.4%

Having prediabetes is a risk factor for getting type 2 diabetes. People with prediabetes may be retested each year. Within the prediabetes A1C range of 5.7 to 6.4 percent, the higher the A1C, the greater the risk of diabetes.

Those with prediabetes are likely to develop type 2 diabetes within 10 years, but they can take steps to prevent or delay diabetes.

Key Points

  • The A1C test is a blood test that provides information about a person’s average levels of blood glucose, also called blood sugar, over the past 3 months.
  • The A1C test is based on the attachment of glucose to hemoglobin, the protein in red blood cells that carries oxygen. Thus, the A1C test reflects the average of a person’s blood glucose levels over the past 3 months.
  • In 2009, an international expert committee recommended the A1C test be used as one of the tests available to help diagnose type 2 diabetes and prediabetes.
  • Because the A1C test does not require fasting and blood can be drawn for the test at any time of day, experts are hoping its convenience will allow more people to get tested—thus, decreasing the number of people with undiagnosed diabetes.
  • In the past, the A1C test was not recommended for diagnosis of type 2 diabetes and prediabetes because the many different types of A1C tests could give varied results. The accuracy has been improved by the National Glycohemoglobin Standardization Program (NGSP), which developed standards for the A1C tests. Blood samples analyzed in a health care provider’s office, known as point-of-care (POC) tests, are not standardized for use in diagnosing diabetes.
  • The A1C test may be used at the first visit to the health care provider during pregnancy to see if women with risk factors had undiagnosed diabetes before becoming pregnant. After that, the oral glucose tolerance test (OGTT) is used to test for diabetes that develops during pregnancy—known as gestational diabetes.
  • The standard blood glucose tests used for diagnosing type 2 diabetes and prediabetes—the fasting plasma glucose (FPG) test and the OGTT—are still recommended. The random plasma glucose test may be used for diagnosing diabetes when symptoms of diabetes are present.
  • The A1C test can be unreliable for diagnosing or monitoring diabetes in people with certain conditions that are known to interfere with the results.
  • The American Diabetes Association recommends that people with diabetes who are meeting treatment goals and have stable blood glucose levels have the A1C test twice a year.
  • Estimated average glucose (eAG) is calculated from the A1C to help people with diabetes relate their A1C to daily glucose monitoring levels.
  • People will have different A1C targets depending on their diabetes history and their general health. People should discuss their A1C target with their health care provider.

Reference: National Institute of Diabetes and Digestive and Kidney Diseases

Last updated January 15, 2017

This information is for general educational uses only. It may not apply to you and your personal medical needs. This information should not be used in place of a visit, call, consultation with or the advice of your physician or health care professional.

Communicate promptly with your physician or other health care professional with any health-related questions or concerns.

Be sure to follow specific instructions given to you by your physician or health care professional.

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