Learn about the A1c and eAG Test

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The A1c and eAG test is performed to assist in treatment decisions and monitor a patient’s diabetes. This lab test can also be performed to diagnose and screen for prediabetes and diabetes. This test is done via a blood draw. Patients who have been diagnosed with diabetes should have this lab test done about two to four times a year during their regular checkup. If a patient is having diabetes’ symptoms, this test is also often done. This test is also referred to as the hemoglobin A1c, glycated hemoglobin, glycohemoglobin, and glycosylated hemoglobin.

How this Test is Used

This test is used to monitor a diabetes patient’s glucose control over time. This helps to determine whether their treatment regimen is effective. This helps to minimize the risk of the patient experiencing diabetes-related complications that can occur when glucose levels are chronically elevated, such as progressive damage to the nerves, eyes, kidneys, cardiovascular system, and other organs.

What is this Test Used For and When is it Ordered?

Depending what type of diabetes the patient has, if there diabetes is well controlled, and the patient’s doctor, the A1c and eAG test may be done two to four times a year. It should be done at least twice a year, according to the American Diabetes Association. When a patient’s diabetes is poorly controlled or when a patient is newly diagnosed, it may be done more often. If the following symptoms occur, diabetes is possible, therefore, this test may be done:

  • Increased thirst
  • Fatigue
  • Slow-healing infections
  • Increased urination
  • Blurred vision

Preparation and Procedure

The blood needed for this can be obtained with a finger prick or by drawing blood from a vein. If the finger prick method is used, the health care professional will use a small, pointed lancet and “prick” one of the patient’s fingers, most often the pointer finger, and squeeze it slightly until a drop of blood is on the surface. They will then place this on what it is they are using to test the sample. If blood is being drawn from a vein, the health care professional will insert a needle into a vein, typically in the hand or crook of the arm, and collect the blood in a vial for testing. Typically, no preparation is needed for this test.

What do the Results Mean?

It is recommended that patients with diabetes keep their A1c levels under 7 percent. The patient’s A1c test report can also include an estimated eAG, which based on the patient’s A1c levels, is a calculated result. Result examples include:

  • A nondiabetic patient having an A1c test result between four percent and six percent.
  • A diabetic patient having an A1c level at 6.5 percent or higher.
  • A patient who is prediabetic having an A1c level between 5.7 percent and 6.4 percent.


Lab Tests Online. (2009). A1c and eAG. Retrieved on September 8, 2010 from Lab Tests Online: https://www.labtestsonline.org/understanding/analytes/a1c/test.html

American Diabetes Association. (2010). Estimated Average Glucose (eAG). Retrieved on September 8, 2010 from the American Diabetes Association: https://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/estimated-average-glucose.html?&utm_source=offline&utm_medium=print&utm_campaign=eag112009