3 hour GTT Instructions

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Instructions for 3 Hour Glucose Tolerance Test

This glucose test is done to evaluate how your body is processing sugar and determine if you have developed Gestational Diabetes.  The test requires a total of 4 blood draws.  The first blood test is done fasting, which means nothing to eat or drink (except water) for 8-12 hours prior to the initial blood draw.  You will then be given a sweetened beverage to drink that has a measured amount of sugar in it.  Blood samples will be collected at timed intervals of 1, 2, and 3 hours after you drink this beverage. 

Preparation for the test:

• You should eat your normal diet prior to the day of testing.
• Do not eat, drink, smoke, or exercise for 8-12 hours before your first blood sample is taken.  You may drink plain water but no other beverages, even if it is diet or sugar-free.
• This test may take up to 4 hours to complete.  Activity can interfere with results so you will be asked to stay within the office for the duration of the test.
• Consider bringing something to read or a project to work on while waiting. 
• You may drink plain water while you wait and during the testing process so feel free to bring in your own cup or water bottle. Do not eat any food or snacks during the test.
• Some people may feel nauseated, light-headed, or sweaty during the testing process. If you do not feel well, please let us know.
• Once the final blood test is drawn you may resume normal eating and drinking.  We expect you will be very hungry at this point and suggest bringing a light snack along (crackers, cheese, granola bar) so that you have something to eat before leaving the clinic and driving a car.

Gestational Diabetes is typically diagnosed when two or more of the results are elevated, but there are other important factors that your doctor may use to make the diagnosis.  Even if you pass the test, there may be other clues that suggest you have developed gestational diabetes.