A1C test recommended as tool to diagnose diabetes
New Orleans, LA
June 5, 2009
Contact Colleen Fogarty
cfogarty@diabetes.org 703-549-1500 ext. 2146
An international expert committee assembled by the American Diabetes Association (ADA), International Diabetes Federation (IDF), and European Association for the Study of Diabetes (EASD) is recommending the A1C assay as the new test for the diagnosis of diabetes. The recommendations from the Committee, which have not yet been officially endorsed by the three diabetes organizations, were reported at a symposium here today at the American Diabetes Association's 69th Scientific Sessions.
The Committee's report, which was published online today and will appear in the July issue of
Diabetes Care
has the potential to usher in a major change in the way diabetes is diagnosed. Currently, two tests are used to diagnose diabetes: the fasting plasma glucose (FPG) or, less commonly, oral glucose tolerance test (OGTT). In making this new recommendation, the Committee examined the relationship between long-term glycemic exposure and complications, and suggested that a reliable measure of chronic glycemic levels, such as A1C (which measures average blood glucose control over the preceding 2-3 months) may serve as a better marker of diabetes and should be used as a diagnostic test.
"A1C values vary less than FPG values and the assay for A1C has technical advantages compared with the glucose assay," said David M. Nathan, MD, Director of the Diabetes Center at Massachusetts General Hospital, and Professor of Medicine at Harvard Medical School, who chaired the Expert Committee. "Also, testing for diabetes using A1C is more convenient and easier for patients who will no longer be required to perform a fasting or oral glucose tolerance test."
In reviewing data examining A1C levels and long-term complications such as retinophathy (damage to small blood vessels in the eye that can lead to vision loss), the Committee concluded that an A1C value greater than or equal to 6.5% be used for the diagnosis of diabetes. This cut-point, notes Dr. Nathan, should not be construed as an absolute dividing line between normal glycemia and diabetes. However, the Committee does conclude that an A1C level of 6.5% is sufficiently sensitive and specific to identify people who have diabetes.
For the identification of people at very high risk to develop diabetes, the Committee concludes that people with an A1C level of greater than or equal to 6% but less than 6.5% are likely to be at highest risk for developing diabetes, but cautions that this range should not be considered an absolute threshold at which risk clearly begins.
"Glucose impairment runs on a continuum, making selection of a specific value where diabetes risk begins somewhat arbitrary. However, those persons whose A1C levels are close to the 6.5% diagnostic level are clearly at higher risk," said Nathan.
The American Diabetes Association recommends screening all adults for diabetes who are overweight and have additional risk factors, such as a family history of diabetes, high blood pressure, or abnormal lipid levels. Adults who do not have any of these risk factors should be tested beginning at age 45. People at risk for diabetes should also receive counseling to maintain normal weight, or lose weight (if necessary), and become more physically active.
The Committee hopes that their report will serve as a stimulus to the international community and professional organizations to consider the use of the A1C assay to diagnose diabetes. The American Diabetes Association responded to the Expert Committee's report by endorsing in principle the use of A1C testing to diagnose diabetes. The Association will also establish a task force to explore the implications of this report including how best to implement its recommendations.
Nearly 24 million Americans have diabetes, a group of serious diseases characterized by high blood glucose levels that result from defects in the body's ability to produce and/or use insulin. Diabetes can lead to severely debilitating or fatal complications, such as heart disease, blindness, kidney disease, and amputations. It is a leading cause of death by disease in the United States.
Symposium, Friday, 2:00 pm CDT
The American Diabetes Association is leading the fight to stop diabetes and its deadly consequences and fighting for those affected by diabetes.
The Association funds research to prevent, cure and manage diabetes; delivers services to hundreds of communities; provides objective and credible information; and gives voice to those denied
their rights because of diabetes. Founded in 1940, our mission is
to prevent and cure diabetes and to improve the lives of all people affected by
diabetes. For more information please call the American Diabetes Association at 1-800-DIABETES (1-800-342-2383) or visit www.diabetes.org. Information from both these sources is
available in English and Spanish.
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