A new test to diagnose diabetes, recommended by the American Diabetes Association, may not work well in African Americans

A study shows that black and white Americans have different amounts of the blood component measured by the test. That component, called hemoglobin A1c, is formed when blood sugar comes into contact with hemoglobin, the protein in red blood cells that make our blood red. That means hemoglobin A1c can act like a dipstick for blood sugar, which is elevated in diabetics. Because too much blood sugar is harmful to our organs, an elevated level of the protein suggests a high risk of suffering diabetes-related complications, like kidney or eye disease. While scientists knew that black people tended to have higher levels of hemoglobin A1c, most thought it was simply a matter of higher blood sugar levels. But according to the new findings, based on a representative sample of Americans without diabetes, black people have consistently more hemoglobin A1c than whites, even when there is no difference in blood sugar, obesity and other factors.