How to Prepare for Your Glucose Tolerance Test
Accurate results depend on proper preparation. Please follow these instructions carefully:
- Dietary Preparation (3 Days Before the Test):
For three days leading up to your test, consume your usual diet, ensuring it includes at least 150 grams of carbohydrates per day. This helps ensure your body is in a normal metabolic state.
(One slice of bread, ½ cup cooked rice, one small fruit, or one cup of milk each contain approximately 15 grams of carbohydrates.) - Fasting (8–12 Hours Before the Test):
You must fast for 8 to 12 hours (but not more than 16 hours) before your appointment. This means no food, sugary drinks, chewing gum, coffee, or tea (even black coffee/tea) during this period. You may drink plain water.
Children only need to fast for 6 hours and babies for 4 hours. - Medications:
Inform your doctor about all medications you are currently taking, including over-the-counter drugs and supplements. They may advise you to temporarily stop certain medications before the test.
Do not stop any prescribed medication without your doctor’s approval. - Avoid Alcohol:
Do not consume alcohol from the evening before the day of the test. - Physical Activity:
Avoid strenuous exercise for 24 hours before the test. - Smoking:
Refrain from smoking on the morning of the test, as it can affect your results. - Rest:
Get a good night’s sleep before your test.
What to Expect on the Day of Your Test
The Glucose Tolerance Test is a multi-step procedure that requires you to remain at the clinic for an extended period.
- Arrival and Initial Blood Draw:
When you arrive, a healthcare professional will take an initial blood sample. This is your “fasting” blood glucose level.
We will need to wait for this result before we can proceed with the test. If your fasting blood glucose level is too high, we will have to discontinue the test. - Glucose Drink:
After the initial blood draw, you will be given a special glucose drink to consume. This drink is very sweet, and you must drink it within 5 minutes. - Waiting Period:
After consuming the drink, you will need to remain at the care centre. During this time, it is important to:- Stay seated and relaxed. Avoid physical activity, walking around, or any strenuous movement.
- Do not eat or drink anything else (except plain water if needed) until the test is complete.
- Refrain from smoking during the entire test.
- Subsequent Blood Draws:
Blood samples will be taken at specific intervals after you drink the glucose solution (e.g., at 1 hour and 2 hours).
The exact timing and number of blood draws will be determined by your doctor’s specific request.
Special Information for Pregnant Women: Screening for Gestational Diabetes
If you are pregnant, your doctor may recommend a Glucose Tolerance Test to screen for Gestational Diabetes. This is a type of diabetes that develops during pregnancy and usually resolves after childbirth. Early detection and management are crucial for the health of both you and your baby.
What to Expect (Gestational Diabetes Screening):
- The preparation steps are the same as outlined above.
- The procedure will generally follow the same timeline and blood draw schedule (initial, 1-hour, and 2-hour samples).
- Even if you feel well, it’s important to complete the test as recommended by your doctor, as gestational diabetes often has no noticeable symptoms.
After Your Test
Once all blood samples have been collected, you are free to leave and resume your normal activities and diet. Your test results will be sent to your doctor, who will discuss them with you and explain what they mean for your health.
If you have any questions or concerns before your Glucose Tolerance Test, please do not hesitate to contact your doctor or clinic staff.