The A1C test is a simple blood test in which a blood sample is drawn, usually from a vein in the arm, and examined in a laboratory. Unfortunately, different laboratories use slightly different numbers to display results, but your doctor should be aware of this; ask your doctor to fully explain results for you and make sure any comparison of past results uses a consistent results scale.

You can also test your A1C level at home using an over-the-counter test approved by the FDA. This test requires a prescription. Ask your doctor for further information if you are interested.

An A1C test should be done initially when you are diagnosed with diabetes. After the first test, the American Diabetes Association recommends the following schedule:

• If you have Type 2 diabetes and do not use insulin, and your blood sugar is well controlled, test twice a year.
• If you have Type 1 diabetes or Type 2 diabetes and use insulin, test every three months.
• If you change treatment, test every three months.

The test results are given in the form of a percentage; this percentage indicates the amount of hemoglobin that is glycated. Normally, 3-6 percent of hemoglobin is glycated, but in people with uncontrolled diabetes the figure can be anywhere between 6-20 percent.

The following table translates A1C results into an average daily blood glucose level and shows what sort of blood glucose control various A1C percentage results indicate.

Most doctors aim to keep the A1C levels for people with diabetes below 8.5 percent and ideally around 7 percent or less. Results higher than 7 percent indicate that your average blood glucose levels are too high. This can be due to too little exercise, too little insulin or diabetes medicine, too much food, the wrong kind of food, stress, illness, or infection.