RESUMO
Many 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]. This study was a clinical trial and carried out on 242 women in Kara-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]. Overall 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 [0/75], 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%]. Two-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