National Diabetes Information
Clearinghouse (NDIC)

A service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH)

he A1C Test and Diabetes

On this page:

What is the A1C test?
How does the A1C test work?
Can the A1C test be used to diagnose type 2 diabetes and prediabetes?
Why should a person be tested for diabetes?
Has the A1C test improved?
How is the A1C test used to diagnose type 2 diabetes and prediabetes?
Is the A1C test used during pregnancy?
Can blood glucose tests still be used for diagnosing type 2 diabetes and prediabetes?
Can the A1C test result in a different diagnosis than the blood glucose tests?
Are diabetes blood test results always accurate?
How accurate is the A1C test?
Can the A1C test give false results?
How is the A1C test used after diagnosis of diabetes?
How does the A1C relate to estimated average glucose?
What A1C target should people have?
Will the A1C test show changes in blood glucose levels?
Points to Remember
Hope through Research
For More Information
Acknowledgments

What is the A1C test?

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. The A1C test is the primary test used for diabetes management and diabetes research.