DefinitionBy Mayo Clinic staff
The A1C test is a common blood test used to diagnose type 1 and type 2 diabetes and then to gauge how well you're managing your diabetes. The A1C test goes by many other names, including glycated hemoglobin, glycosylated hemoglobin, hemoglobin A1C and HbA1c.
The A1C test result reflects your average blood sugar level for the past two to three months. Specifically, the A1C test measures what percentage of your hemoglobin — a protein in red blood cells that carries oxygen — is coated with sugar (glycated). The higher your A1C level, the poorer your blood sugar control and the higher your risk of diabetes complications.
- A1c and eAG. American Association for Clinical Chemistry. http://www.labtestsonline.org/understanding/analytes/a1c/test.html. Accessed Nov. 7, 2012.
- Malkani S, et al. Implications of using hemoglobin A1C for diagnosing diabetes mellitus. The American Journal of Medicine. 2011;124:395.
- A1C. American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/a1c/. Accessed Nov. 7, 2012.
- Nathan DM, et al. International Expert Committee report on the role of the A1C assay in the diagnosis of diabetes. Diabetes Care. 2009;32:1327.
- The A1C test and diabetes. National Institute of Diabetes and Digestive and Kidney Diseases. http://diabetes.niddk.nih.gov/dm/pubs/A1CTest/. Accessed Nov. 7, 2012.
- How often should A1c and LDLs be checked? American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/ask-the-expert/ask-the-pharmacist/archives/how-often-should-a1c-and-ldls.html?&print=t. Accessed Nov. 8, 2012.
- Castro RM (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 9, 2012
- American Diabetes Association. Standards of medical care in diabetes — 2013. Diabetes Care. 2013:36:S1.