Hemoglobin A1C test

During your treatment, your doctor will use a Hemoglobin A1C test to help manage your diabetes. Unlike the blood glucose meter that you will use at home, a Hemoglobin A1C test shows your average blood sugar level for the past few months. This test is used to check whether an individual has diabetes or to see if your treatment for diabetes is working correctly. You may see this test written as HbA1C, glycated hemoglobin, or just A1C.

When your doctor checks for diabetes your A1C test should be 6% or less.1

  • If it is 6.5% or higher, it means you have diabetes, but the test should be done again to confirm the diagnosis.1
  • If it is between 5.7% and 6.4%, you are at risk for getting diabetes. This means you should start doing things that can keep you from developing diabetes. For example, becoming more active and losing weight (if you are overweight).1
  • If you already know you have diabetes, you will want to keep your A1C 7% or less.1 This corresponds to an average blood sugar of 154 mg/dL (8.6 mmol/L).2 You should check with your doctor for what your exact levels should be, as not everyone with diabetes is the same.

Testing with a glucose meter vs. A1C

The result you get with a glucose meter is your glucose level at that exact moment in time. An A1C test is an average. The most important information for you is to see that your blood sugar levels stay somewhat consistent as the day goes on.

Your doctor will check for big gaps in blood sugar changes to ensure no big changes are happening throughout your day.

In other words, you will want to make sure your results stay as close to the same as possible. Your doctor will check the results and give you advice on how to keep big changes in your readings from happening (if they are happening).

When is A1C testing done?

This is dependent on if you have diabetes and what your last A1C test showed.3

  • If you had the test and your A1C was less than 5.7%, this means you do not have diabetes. But, because this number is a little higher than desired, you should have a test done every 3 years to make sure it doesn’t get worse.
  • If you had an A1C that was between 5.7% and 6.4%, it means you are at risk for getting diabetes. You should try to maintain a healthy lifestyle to make sure your A1C doesn’t get worse. In this case, you should get an A1C test every 1 to 2 years.
  • If you have diabetes and you have your blood glucose levels under control, your A1C test will be done every 6 months.
  • If you have diabetes but have trouble controlling your blood sugar, or have changed diabetes treatment medication recently, you should have your A1C test every 3 months.

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1UpToDate. Patient education: Hemoglobin A1C tests (The Basics). UpToDate. Wolter Kluwer, 2020
2Wexler DJ, Nathan DM, and Mulder JE. Patient education: Type 2 diabetes: Insulin Treatment (Beyond the Basics). UpToDate. Wolters Kluwer, 2020
3UpToDate. Patient education: Hemoglobin A1C tests (The Basics). UpToDate. Wolter Kluwer, 2020