November 2025
The A1C test is a blood test that provides information about a person’s average levels of blood glucose over the past three months. It is used to screen for diabetes and pre-diabetes, as well as to monitor blood sugar control in people who have diabetes.
How does the A1C test work?
The A1C test measures the attachment of glucose to hemoglobin, the protein in red blood cells that carries oxygen. Red blood cells continually form and die but typically live for about three months. The A1C test reflects the average of a person’s blood glucose levels over this time.
Who should get the A1C test?
Ask your doctor if A1C testing makes sense for you, and how often you need it done. Those with prediabetes and diabetes will require more frequent testing than those without.
Those with risk factors should also consider testing every two to three years. According to the CDC, you are more at risk of developing diabetes or prediabetes if you are:
- Overweight or obese. (That’s a BMI of 25+)
- 45 years old or older.
- Have a sibling or parent with type 2 diabetes.
- Are physically active less than three times per week.
- Have a history of gestational diabetes (That’s diabetes while you’re pregnant.)
- Have given birth to a baby that weighed more than nine pounds.
What do the results mean?
The A1C test result is reported as a percentage. The higher the percentage, the higher a person’s blood glucose levels.
If you took the A1C test as a screening test, here’s what your results mean:
- A normal A1C level is 5.6% or lower.
- An A1C of 5.7% to 6.4% means you are in the pre-diabetic range. This means you are at increased risk of developing diabetes and should start making diet and lifestyle changes to reduce your blood sugar and your risk of developing diabetes later on.
- An A1C of 6.6% or higher indicates that you are in the diabetes range and should pursue further diabetes screening with your doctor.
If you have diabetes, the American Diabetes Association recommends that you get your A1C checked at least twice a year — and more often if you’re not meeting your treatment goals.
The lower your A1C, the better your diabetes is being managed. For most diabetics, the goal is to reduce A1C to less than 7%.
