Blood Glucose

A1c: Why Is It Important?

January 11, 2017   /

A1c: Why Is It Important?

What is A1c?
A1c reflects your average glucose levels during the past 6–8 weeks and is a useful indicator of how well your blood glucose is controlled during this time period.

A1c also is known as:

  • Hemoglobin A1c
  • Glycosylated hemoglobin
  • Glycated hemoglobin
  • Glycohemoglobin

Why is A1c important?
You can delay or prevent complications of diabetes, such as progressive damage to the kidneys, eyes, cardiovascular system, and nerves, if A1c is kept below 7%. As A1c increases, so does the risk of complications.

How often should you test your A1c?
Patients who are meeting treatment goals and who have stable glycemic control should test their A1c two times per year (every 6 months). Patients whose therapy has changed or who are not meeting their glycemic goals should test their A1c quarterly.

What does the test result mean?
Diabetes is considered as under control when your A1c is 7% or less, which corresponds to an average blood glucose of about 154 milligrams (mg)/deciliter (dL) or less. A 1% change in A1c represents a change of about 30 mg/dL in average blood glucose (correlations may vary from lab to lab).

Certain medical conditions may make your A1c inaccurate:

  • Kidney failure
  • Liver disease
  • Acute or chronic blood loss
  • Sickle cell disease
  • Gestational diabetes


References and recommended readings
American Diabetes Association®. Standards of medical care in diabetes—2012. Diabetes Care [serial online]. 2012;35(suppl 1):S11-S63. Available at: Accessed July 27, 2012.

National Diabetes Information Clearinghouse (NDIC). The A1c test and diabetes. Available at: Accessed July 27, 2012.


Review Date 7/12