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ADA – International Expert Committee Recommends A1c Test to Diagnose Diabetes

Jun 9, 2009

This is the first major departure from the way we’ve been diagnosing diabetes for more than 30 years,” David M. Nathan, M.D., of Harvard Medical School who chaired the expert committee, told the press at the start of the annual meeting of the American Diabetes Association. … Full Story

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 at the American Diabetes Association’s 69th Scientific Sessions.

The committee’s report, which was published online 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 retinopathy (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 for developing 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 the 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.

Practice Pearls:
Explain that an international committee has recommended that an A1c assay should be used to diagnose diabetes instead of a fasting plasma glucose or oral glucose tolerance test.
The committee recommends patients with an A1c of 6.5% or higher should be diagnosed with the disease.
The ADA 69th Scientific sessions, June 5th, 2009


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