Which is the threshold glycose value for further investigation in pregnancy?

The aim of this study was to investigate the lower threshold glycose value in a 50 gr-1 hour screening test for further testing in diagnosing gestational diabetes mellitus (GDM). Our study consisted of 602 pregnant women between 24-28 weeks of gestation, who received a 50 gr glycose load followed by glycose determination one hour later. After screening 273 out of 602 women showed test serum glycose values > 125 mg/dl. All 273 women received a 100 gr 3-hour glycose tolerance test (GTT). Thirty out of 273 women were found to have carbohydrate intolerance. The overall incidence of GDM was 4.98%. When the threshold glycose value was > or = 130 mg/dl the incidence of GDM was 17.8%, but lowering the threshold to 126 mg/dl a further 1.3% of the women showed carbohydrate intolerance. In the above threshold value the sensitivity was 100% but the specificity was only 54%. However, we recommend 126 mg/dl threshold for GTT since this threshold allows for the diagnosis of all women with carbohydrate intolerance during pregnancy.