[Multicenter study on screen method for gestational diabetes].

OBJECTIVE: To investigate the feasibility of using random blood glucose to screen gestational diabetes mellitus (GDM).

METHOD: The random blood glucose was determined in 1 038 pregnant women between 24 and 32 gestational weeks. Then 50 gram glucose challenge test (50 g GCT) was performed followed immediately. Finally, 75 gram oral glucose tolerance test (75 g OGTT) was done without dietary control for 3 days. If two values of four were abnormal, GDM was diagnosed. Impaired glucose tolerance (IGT) was diagnosed if only one value was abnormal or the 2nd hour value ranged from 120 to 164 mg/dl.

RESULTS: (1) The determination of the three steps was completed in 948 cases. Among them, 42 cases (4.4%) were GDM, 372 cases (39.2%) were IGT and other 534 cases were normal. (2) In the normal group, the random blood glucose were different in fasting and postprandial times. No difference was found among blood glucose values determined of 50 g GCT at different times except that the value of 50 g GCT 1 hour postprandial was higher than the value at other times. There was no significant association between random blood glucose and 50 g GCT. (3) The sensitivity and specificity were 50.0% and 67.7%, when IGT was diagnosed using the cut point of 6.4 mmol/L (115 mg/dl) of random blood glucose, which was similar with 51.1% of sensitivity and 71.2% of specificity when using >or= 7.8 mmoL/L (140 mg/dl) as the cut point of 50 g GCT. If 6.4 mmol/L (115 mg/dl) was used as the cut point in GDM group the sensitivity would be 80.0%, which was much higher than that of IGT group and the specificity was 61.2%. In this study, if the value of >or= 8.3 mmoL/L (150 mg/dl) was used as the cut-point of 50 g GCT to screen the GDM, the sensitivity decreased only 2.0% while the specificity increased more than 10.0%.

CONCLUSIONS: (1) The determination of random blood glucose to screen GDM couldn't replace the 50 g GCT, but it can be used as a complemental method and can be used repeatedly at any gestational age and convenience the pregnant women and the doctors. (2) The value of 8.3 mmol/L (150 mg/dl) was used as the cut-point of 50 g GCT, the specificity would be increased and the requirement for OGTT would be lowered markedly, which would reduce economic and psychological stress.