<prompt> Which one of the investigation modalities can diagnose gestational diabetes in a primigravida?HbA1CFBSGCTGTT  <response>: The diagnosis of gestational diabetes is based on the result of the glucose tolerance test. If a GCT is ve a GTT should be done to confirm gestational diabetes. Procedure: Screening with 50g, 1-hr glucose challenge test GCT Plasma glucose 140 mgdL. Diagnosis with 100g, 3-hr glucose tolerance test GTT Fasting - 95 mgdL 1 hr - 180 mgdL 2 hrs - 155 mgdL 3 hrs - 140 mgdL Two abnormal values on GTT confirm gestational diabetes. 