Comparison of Diagnostic Value of Fasting Plasma Glucose with 100 Gram Oral Glucose Tolerance Test in Gestational Diabetes Mellitus Screening

IntroductionMany different tests have been introduced for screening of gestational diabetes mellitus (GDM).The Objectives of this study were comparison of diagnostic value of fasting plasma glucose (FPG) with 100 gram oral glucose tolerance test (OGTT) and determining the suitable cut-off point of plasma glucose with best sensitivity and specificity for diagnosis of gestational diabetes mellitus (GDM).Materials and MethodsThis study was a clinical trial and Carried out on 242 women in Karaj-Iran. After doing 50 gram glucose challenge test (GCT), if 1-hour plasma glucose was ≤130 mg/dl, the 3 hours 100 gram OGTT was performed. The diagnostic values of FPG and 1, 2 and 3 hours plasma glucose were compared by receiver operating characteristic curve (ROC). ResultsOverall 50 gram GCT was positive in 41/3%. Then 100 gram OGTT for these was performed, 36% were identified as GDM. With using below surface of ROC curve for FPG (o/75), 1-hour (0/87), 2-hour (0/95) and 3-hour (0/75) plasma glucose determined that FPG with cut-off point ≤91 mg/dl had 63.89% sensitivity rate and 76/56% specificity rate for diagnosis of GDM. However, 2-hour plasma glucose with cut-off point ≤153 mg/dl had highest level of sensitivity rate (91/67%) and specificity rate (89/06%).ConclusionTwo-hour glucose with cut-off point ≤153 mg/dl had the best sensitivity and specificity rate in diagnosis of GDM. Therefore, 100 gram OGTT recommended for screening of GDM.