Fasting plasma glucose versus glucose challenge test: screening for gestational diabetes and cost effectiveness

Objective: To compare the performance in screening for gestational carbohydrate intolerance of the 1-h 50-g glucose challenge test (GCT), fasting plasma glucose (FPG) and fasting capillary glucose (FCG). Design and methods: FPG and FCG were measured at the same time as the GCT in 188 women. Gestational carbohydrate intolerance was diagnosed according to the Canadian Diabetes Association criteria. We constructed receiver operator characteristic (ROC) curves and compared the sensitivity and specificity of the FPG, FCG and GCT. Results: Gestational diabetes was diagnosed in 11.2% women and gestational impaired glucose tolerance in 8.4%. The areas under the ROC curves for the FPG, the GCT and the FCG were not statistically different (P = 0.26). The GCT yielded a better specificity than the FPG and the FCG for a comparable level of sensitivity. Conclusions: The GCT is better than the FPG in our population and is cost effective.