Common diabetes diagnosis test fails to catch cases by more than 70%
According to new research from City of Hope, presented Saturday at a news conference during ENDO 2019, the Endocrine Society’s annual meeting in New Orleans, LA, the hemoglobin A1c blood test – one of the most commonly used diagnostic tests for type 1 and type 2 diabetes – is not very reliable at detecting the disease among most patients tested. In fact, test results for those patients indicated that their blood glucose levels were normal.
“Based on these findings, A1c should not be solely used to rule out diabetes, particularly if a patient has prediabetes or has increased risk factors for developing diabetes, “said lead researcher Maria Mercedes Chang Villacreses, M.D., of City of Hope’s Diabetes and Metabolism Research Institute. “It should be used in conjunction with the oral glucose test for increased accuracy.”
Led by Ken C. Chiu, M.D., City of Hope professor of clinical diabetes, endocrinology & metabolism, the study, described in a City of Hope news release, included 9,000 adults from the 2005-2014 National Health and Nutrition Examination Survey who did not have a diabetes diagnosis. The participants received both an A1c test and an oral tolerance glucose test, and the researchers compared the results. The researchers found the A1c test didn’t catch 73 percent of diabetes cases that were detected by the oral glucose test.
The hemoglobin A1c test, also known as HbA1c, shows a person’s average level of blood sugar over the past two to three months. The test is used to diagnose diabetes, and also to find out whether a person with the disease has blood sugar levels within a certain target range. The simple blood test has grown in popularity because it doesn’t require patients to fast, unlike the two other most common diabetes tests.
The researchers also found race and ethnicity had a significant impact on the accuracy of A1c. It was more likely to detect abnormal glucose levels in non-Hispanic whites than in non-Hispanic blacks or Hispanics.
According to the Centers for Disease Control and Prevention, 30.3 million U.S. adults have diabetes, and one in four of them don’t know they have it. Diabetes is the seventh leading cause of death in the United States, and is the leading cause of kidney failure, lower-limb amputations and adult blindness. In the last 20 years, the number of adults diagnosed with diabetes has more than tripled.
