The A1c test 

s a common blood test used to diagnose type 1 and type 2 diabetes. If you're living with diabetes, the test is also used to monitor how well you're managing blood sugar levels. The A1C test is also called the glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C or HbA1c test.

An A1C test result reflects your average blood sugar level for the past two to three months. Specifically, the A1C test measures what percentage of hemoglobin proteins in your blood are coated with sugar (glycated). Hemoglobin proteins in red blood cells transport oxygen.

The higher your A1C level is, the poorer your blood sugar control and the higher your risk of diabetes complications.

A1C test results are reported as a percentage. A higher A1C percentage corresponds to higher average blood sugar levels. Results for a diagnosis are interpreted as follows:

Below 5.7% is normal.

5.7% to 6.4% is diagnosed as prediabetes.

6.5% or higher on two separate tests indicates diabetes.