A1C test

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Why it's done

By Mayo Clinic staff

In June 2009, an international committee composed of experts from the American Diabetes Association, the European Association for the Study of Diabetes and the International Diabetes Federation recommended that the A1C test be the primary test used to diagnose prediabetes, type 1 and type 2 diabetes.

After a diabetes diagnosis, the A1C test is used to monitor your diabetes treatment plan. The A1C test measures your average blood sugar level for the past two to three months. Unlike daily blood sugar monitoring, which only measures your blood sugar level at a point in time, the A1C test indicates how well your diabetes treatment plan is working overall.

Your doctor will likely use the A1C test when you're first diagnosed with diabetes. This also helps establish a baseline A1C level. The test may then need to be repeated while you're learning to control your blood sugar.

Later, how often you need the A1C test depends on the type of diabetes you have and how well you're managing your blood sugar. For example, the A1C test may be recommended:

  • Twice a year if you have type 2 diabetes, you don't use insulin, and your blood sugar level is consistently within your target range
  • Three to four times a year if you have type 1 diabetes
  • Four times a year if you have type 2 diabetes, you use insulin to manage your diabetes, or you have trouble keeping your blood sugar level within your target range

You may need more frequent A1C tests if your doctor changes your diabetes treatment plan or you begin taking a new diabetes medication.

MY00142

June 13, 2009

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