How is the Screening Test done?
One-hour screening test (GLT): You will drink a 50-gram sugar soda within 5 minutes time. Your blood is drawn 1 hour later. You do not have to fast for this test and there are no special dietary restrictions. You should remain seated throughout the entire hour and should not smoke. Three-hour diagnostic test (OGTT): If the 1-hour test is abnormal, a 3-hour glucose tolerance (OGTT) test is usually performed. This blood test is done in the morning after you fast for 8 hours but not more than 12. A fasting blood sugar test is drawn and then you drink the 100-gram sugar soda within 5 minutes. Blood is drawn at 1, 2 and 3 hours after the drink. Again, you should remain seated throughout the entire hour and should not smoke.
When you arrive for the test, you’ll be given a sugar solution that contains 50 grams of glucose. The stuff tastes like a very sweet soda pop (it comes in cola, orange, or lime flavor), and you have to get all of it down in five minutes. Some centers keep it chilled or let you pour it over ice and drink it cold. An hour later (bring a book or magazine!), your practitioner or a technician will take a blood sample from your arm to check your blood sugar level. The idea is to see how efficiently your body processes sugar. Results should be available in a few days. If the reading is abnormal (too high), which happens 15 to 23 percent of the time, your practitioner will have you come back for a three-hour glucose tolerance test to see if you really do have gestational diabetes. The good news is that most women whose screening test shows elevated blood sugar don’t turn out to have gestational diabetes.
