Predictive value of 1 hour 50 g oral glucose load screening test for gestational diabetes mellitus compared to 3 hour oral glucose tolerance test in high risk pregnant women.

A prospective study for detecting gestational diabetes mellitus was undertaken to evaluate the use of one hour plasma glucose level after 50 g glucose loading test (1-hr GLT) as compared to the traditional 3-hours 100 g oral glucose tolerance test (3-hr OGTT) in 396 high risk cases. Each patient, had 1-hr GLT and 3-hr OGTT performed in a separate week. Forty-two cases (10.6%) who had abnormal 3-hr OGTT were classified as gestational diabetes (GDM). One hundred and sixty cases (40.4%) had an abnormal 1-hr GLT (plasma glucose level > or = 140 mg/dl). Thirty-six of these 160 cases (22.5%) had an abnormal 3-hr OGTT. In 236 women (59.6%) that had normal 1-hr GLT (plasma glucose level < 140 mg/dl) only 6 cases (2.5%) had an abnormal 3-hr OGTT. If 1-hr plasma glucose level > or = 150 mg/dl was used as the cutoff point, 110 cases (27.8%) were found to have abnormal 1-hr GLT, and 35 of these 110 cases (31.8%) had an abnormal 3-hr OGTT. Seven of 286 women (2.4%) that had normal 1-hr GLT (plasma glucose level < 150 mg/dl) had an abnormal 3-hr OGTT. The sensitivity and specificity of the 1-hr GLT when abnormal 3-hr OGTT was used as gold standard for detecting GDM were 85.7% and 65% respectively (BS > or = 140 mg/dl). Whereas the sensitivity and specificity were 83.3% and 78.8% respectively when plasma glucose level > 150 mg/dl was used as the cut point.(ABSTRACT TRUNCATED AT 250 WORDS)