Emory University researchers have found that a test commonly used to help identify women with diabetes during pregnancy may be an accurate, convenient and economical way to screen the general population for unrecognized diabetes and prediabetes.

The researchers screened 1,573 volunteer participants who had never been diagnosed with diabetes.

"Widespread use of the glucose challenge test (GCT) to screen Americans for prediabetes and diabetes could provide a major opportunity to improve the health of more than 40 million people," said lead study author Lawrence S. Phillips, MD, Emory University School of Medicine Professor of Medicine, Division of Endocrinology.

At a first visit, at different times of the day and without restriction of meals, participants were given a 50-gram glucose drink. Glucose was measured both before the drink (random glucose) and an hour after the drink (GCT glucose).

At a follow-up visit held in the morning after an overnight fast, participants had measurement of hemoglobin A1c (a standard test used to monitor diabetes), and a 75-gram oral glucose tolerance test (OGTT). The OGTT is the "gold standard" for diagnosing diabetes and prediabetes.

After screening, researchers found that 4.6 percent of the participants had previously unrecognized diabetes, and 18.7 percent had prediabetes.

The GCT was the most accurate screening test for these problems, significantly better than the random glucose or A1c tests.

Since the good performance of the GCT was unaffected by the time of day, or times after meals, the GCT could be performed during a routine office visit.

If a patient''s GCT glucose level is low, he/she wouldn''t need to be screened again for another two or three years, but if the GCT glucose level is high, patients would need a confirmatory oral glucose tolerance test.

This approach is similar to screening women for diabetes during pregnancy. GCT screening is almost universal for women in their sixth month of pregnancy.

The GCT provided consistent results for a diverse group of patients - old and young, normal weight and overweight, men and women, with and without a family history of diabetes, etc. The GCT also appeared to be less expensive than other screening strategies.

"Glucose challenge test screening could help improve disease management by permitting early initiation of therapy aimed at preventing or delaying the development of diabetes and its complications," said Phillips.