<prompt> Gestational diabetes is diagnosed by:Glucose tolerance test GTTRandom blood sugarFasting and postprandial blood sugar24 hours blood glucose profile  <response>: Gestational diabetes is diagnosed by glucose tolerence test. GTT is done at 24 to 28 weeks of gestation . GTT should be performed in the morning after an overnight fast of atleast 8 hrs Diagnosis of GDM is made when any of the following plasma glucose values are exceeded Fasting 92mgdl or if that after 2hours of ingestion of 100g glucose is over 120mg100mL However if the fasting plasma glucose value is more than or equal to 126mgdL ,andif confirmed on repeat test the women is considered as Diabetic even without running GTT test. Reference: DC.Duttas textbook of OBG, 9th edition,page 262 