The A1C test is a blood test that provides information about a person’s average levels of blood glucose over the past 3 months. The A1C test is sometimes called the hemoglobin A1c, HbA1c, glycosalated hemoglobin or glycohemoglobin test. The A1C test is the primary test used for diabetes-management monitoring.
The test is based on the attachment of glucose to hemoglobin, the protein in red blood cells that carries oxygen. In the body, red blood cells are constantly forming and dying, but typically they live for about 3 months. Thus, the A1C test reflects the average of a person’s blood glucose levels over this time period. The A1C test result is reported as a percentage. The higher the percentage, the higher a person’s blood glucose levels have been. A normal A1C level is below 5.7 percent. If you have diabetes, your A1C levels should be check by your doctor at least annually.
Source: National Diabetes Information Clearinghouse