New Method Makes Diabetes Blood Sugar Tests Easier to Understand


SAN FRANCISCO — Although it sounds complicated, a new math formula could make it much easier for people with diabetes to keep track of their blood sugar.

Researchers in the U.S. and the Netherlands have developed a formula to convert the results of a test done in the doctor’s office—the hemoglobin A1C blood test—into a number that more closely matches the results people get from pricking their finger and testing their blood at home.

If all goes as planned, patients should be getting a lab-test result called the estimated average glucose (eAG), which lets them know how well they’ve been controlling blood sugar in recent months.

"Patients can translate what they're doing at home to what we're doing in the clinical chemistry lab,” said Robert J. Heine, MD, professor of diabetology at VU University Medical Center in Amsterdam and co-chair of the International A1C-Derived Average Glucose (ADAG) study. The results of the study were presented at the American Diabetes Association's annual meeting in San Francisco.

For nearly 25 years physicians have been giving patients results from the hemoglobin A1C test, which measures the amount of sugar stuck to red blood cells. The results come back as a percentage, and the American Diabetes Association recommends that people aim for a level of 7% or less.

It’s a good measure of blood glucose control over a two- to three-month period, but it’s not a good match for blood-sugar monitoring that patients do at home.

Those at-home methods report results in milligrams per deciliter (mg/dL). Normal blood sugar ranges from 90 to 130 mg/dL.

With the new estimated average glucose, hemoglobin A1C results will be expressed in milligrams per deciliter for patients (doctors will still get A1C lab results in addition to eAG results).

Dr. Heine and colleagues tested the formula in a study in which they compared data from 507 patients who used continuous glucose monitors, and blood glucose monitors in 10 centers around the world. Patients had either type 1 or type 2 diabetes or no diabetes at all.

Now that there's a way to translate A1C results into familiar units, more study is needed to see if it helps people control their blood sugar, said study investigator Edward S. Horton, MD, professor of medicine at Harvard Medical School.

"We're just promoting this change now," Dr. Horton said. "We're hoping that it's going to improve things, but we don't have the data yet."

The study will be published in the August issue of Diabetes Care.

By Sean Kelley