How is a glucose test done?
The simplest glucose test is done by taking your blood before and after you eat. However, this test is not sensitive enough to diagnose patients with “pre-diabetes.” Before and during pregnancy there is usually a two-step approach to diagnosing diabetes: The initial screening test is called GCT, or Glucose Challlenge Test, and it’s often done between 24 and 28 weeks of pregnancy. The GCT does not diagnose diabetes but it screens women who may be at risk and who may need a 3-hour GTT. The GCT consists of measuring the serum glucose concentration 1 hour after the woman has drunk a 50 g (some use 75 g) oral glucose load. Values below 130 dg/mL are usually considered normal, values above 140 mg/dL are usually considered abnormal, and values between 130 and 140 mg/dL are “in between.” A glucose threshold value >140 mg/dL identifies approximately 80% of women with pregnancy diabetes (GDM), and the yield is further increased to 90% by using a cutoff of >130 mg/dL. Women whose serum glucose is
