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Variations in oral glucose tolerance tests: the 100- versus 75-g controversy
L E Brustman1, B D Gela, M Moore
1Department of Obstetrics and Gynecology, Our Lady of Mercy Medical Center, Bronx, New York, USA.
Journal of the Association for Academic Minority Physicians : the Official Publication of the Association for Academic Minority Physicians
|January 1, 1995
Summary
Comparing oral glucose tolerance tests, a 75-g, 3-hour test yielded lower glucose values than the 100-g test. This difference impacts gestational diabetes mellitus diagnosis, requiring new diagnostic thresholds.
Area of Science:
- Obstetrics and Gynecology
- Endocrinology
- Clinical Chemistry
Background:
- Gestational diabetes mellitus (GDM) diagnosis relies on oral glucose tolerance tests (OGTT).
- Standard diagnostic criteria often use a 100-g, 3-hour OGTT.
- Alternative OGTT protocols, such as a 75-g, 3-hour test, are also employed.
Purpose of the Study:
- To compare the diagnostic yield of a 75-g, 3-hour OGTT versus a 100-g, 3-hour OGTT in pregnant women.
- To evaluate the impact of different OGTT protocols on GDM diagnosis rates.
Main Methods:
- A comparative study involving 32 pregnant women.
- Each participant underwent both a 100-g and a 75-g OGTT within one week, serving as their own control.
- Glucose levels were measured at 1, 2, and 3 hours post-glucose load for both tests.
Main Results:
- A strong positive correlation was observed between the 75-g and 100-g OGTT results.
- However, 1-, 2-, and 3-hour glucose values were significantly higher with the 100-g test compared to the 75-g test.
- Using the National Diabetes Data Group criteria, the 100-g OGTT identified 16/32 women with GDM, while the 75-g OGTT identified only 6/32.
Conclusions:
- The 75-g, 3-hour OGTT yields lower glucose values than the 100-g, 3-hour OGTT.
- Direct comparison of results between the two OGTT protocols is problematic without revised diagnostic thresholds.
- The choice of OGTT protocol significantly influences GDM diagnosis rates.
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