A1C Test for Diabetes Diagnosis
In 2010, the American Diabetes Association recommended that the A1C blood test be added as an option for diagnosing diabetes. The A1C test joins two other diagnostic blood tests: the fasting plasma glucose (FPG) test and the oral glucose tolerance test (OGTT). Unlike these other two tests, the A1C does not require that a patient fast before the test. In addition, the A1C measures a person’s average blood sugar (glucose) levels over several months. The FPG and OGTT evaluate blood glucose levels only for the day of test. For diagnosis, A1C levels above 6.5% indicate diabetes. Levels between 5.7 – 6.4% indicate pre-diabetes.
Estimated Average Glucose (eAG)
Patients with diabetes should get their A1C checked every 3 months or at least twice a year. Most patients with diabetes should aim for an A1C of around 7%. In discussing the results of your A1C test, your doctor may use a relatively new term called “estimated average glucose” or eAG. The eAG converts the percentage of the A1C test into the mg/dL units patients are familiar with from their daily home glucose monitoring. An A1C of 7% is equal to an eAG of 154 mg/dL.
New Drug Approvals
- Liraglutide (Victoza) is a once-daily injectable GLP-1 inhibitor similar to exenatide (Byetta)
- Saxagliptin (Onglyza) is a DPP-4 inhibitor drug, also called a gliptin. It belongs to the same class of drugs as sitagliptin (Januvia).
- Bromocriptine mesylate (Cycloset) is a dopamine agonist drug, similar to medications used to treat Parkinson’s disease.
- The FDA is currently reviewing safety data concerning rosiglitazone (Avandia) and increased risk of heart attack and heart failure. The FDA is planning to make recommendations by summer 2010 on whether rosiglitazone should remain on the market. The American Heart Association and the American College of Cardiology issued an advisory in February 2010 that thiazolidinedione drugs, which include rosiglitazone and pioglitazone (Actos), not be initiated in patients with moderate or severe heart failure.
- Exenatide (Byetta) may cause kidney problems, including kidney failure, and should not be used by patients with poor kidney function.
- Sitagliptin (Januvia, Janumet) may cause severe and sudden inflammation of the pancreas (acute pancreatitis).
Review Date: 04/01/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.