A1c is a test that shows the average level of blood sugar over the past 2 to 3 months. People who have diabetes need to have this test done regularly to see whether their blood sugar levels have been staying within a target range. This test is also used to diagnose diabetes.
A1c test results show your average blood sugar level over time. The result is reported as a percentage. Your goal is to keep your hemoglobin A1c level as close to your target level as possible. You and your doctor will work together to set your safe target level.
The result of your A1c test can also be used to estimate your average blood sugar level. This is called your estimated average glucose, or eAG. Your eAG and A1c show the same thing in two different ways. They both help you know about your average blood sugar over the past 2 to 3 months.
The table below shows A1c with estimated average glucose.