An oral glucose suppression test is done to find out if the pituitary gland is releasing too much growth hormone (GH). The pituitary gland is a small gland (about the size of a pea) in the brain. It releases hormones into the bloodstream that affect growth. During this test, medicine will be used to cause blood glucose levels to rise which should make GH levels go lower.
Some people call glucose levels, “blood sugar.”
- The medicine that will be given to your child is called a glucose beverage. It is swallowed. It will taste “sugary.”
The amount of the glucose beverage is based on your child’s weight. The nurse in the infusion clinic will measure your child’s height and weight before starting the test. All of the medicine will need to be swallowed within 5 minutes.
Samples of blood are collected in a timed manner by the infusion nurse and sent to the laboratory. The laboratory measures both growth hormone and glucose levels in the blood. Your doctor will review the test results and notify you of the results.
Your child should eat however they normally eat for several days before this test. You do not have to limit or “cut back” on carbohydrates. Let your doctor know if your child follows any special diet before this test is done.
The night before the test
- At the time of the test, your child should be free of any illness.
- Your child should have nothing to eat or drink after midnight the night before the test, except tap water. This means NO breakfast, breath mints, chewing gum, flavored or bottled water.
- Your child should not take any medicine before the test unless your doctor tells you the medicine may be given. You may bring the medicine with you to the test so it may be given when the test is finished.
- Your child should go to bed at the usual time.
- Be sure to tell the doctor if your child has any allergies or reactions to medicine, food preservatives or dyes. Tell the doctor about the allergy and its effects on your child.Effects include rash, hives, itching, shortness of breath, wheezing, coughing, swelling of face, lips, tongue or throat or any other symptoms involved.
- Be sure to tell the doctor if your child has recently or is currently taking steroids.
The day of the test
- Your child should feel well and not have a fever the day of the test.
- He or she should come to the clinic dressed comfortably. It would be best if your child wears a short-sleeved shirt to the test.
- Bring books, toys or games for your child to use during the test.We have a TV with a DVD player, so feel free to bring a movie.
How the test is done
The test will be done in the Infusion Clinic (Picture 1).
This test may take up to 3 hours. Parents are asked to stay with their child during the test. Since we have limited seating, family members other than 2 parents may be asked to sit in the waiting room during the test.
- The nurse will start an intravenous line (IV). The nurse may offer to put lidocaine-prilocaine cream on your child’s arm before starting the IV. The cream will start to work about 20 minutes after it is put on. It is used to decrease pain when starting an IV.
- Once the IV is in place, all of the blood samples will be drawn from the IV.
- Blood samples of glucose and GH will be drawn before the medicine is given, and then 30 minutes, 60 minutes, 90 minutes and 120 minutes after the glucose beverage is swallowed.
- Your child should not feel any discomfort when blood is drawn since it will be drawn from the existing IV.The total amount of blood is small (about 5 teaspoons).
After the test
When the test is over, your child may have his or her regular foods. Feel free to bring a snack with you for your child to eat after the test.
Your child's doctor will contact you about the test results and plan for medical care.
Side effects of medicines
Glucose Beverage: Some patients may experience nausea after taking the glucose beverage.
Parent information for Crossroads Registration
Crossroads Registration is located on the main level near the Crossroads Welcome Desk, between the Crossroads elevators and the Tower elevators. Follow the Blue Path to the Crossroads lobby where the Green Path meets the Blue Path.
The Infusion Clinic can be accessed from the Tower elevators (between Crossroads Registration and Urgent Care along the Blue Path). Take the Tower elevators to level 4 and turn right into Suite D.
These three parking options are available:
- Park in the Hospital Garage on Children’s Drive.Once inside, turn right and follow the Blue Path.It meets the Green Path at the Crossroads Registration Area.
- Park in the Outpatient Care Garage on 18th Street. Enter the hospital and follow the Blue Path.It meets the Green Path at the Crossroads Registration Area.
- Use the valet parking on Children’s Drive or 18th Street.Enter the hospital and follow the Blue Path.It meets the Green Path at the Crossroads Registration Area.
If you have any questions, contact the Section of Endocrinology at 614-722-4425.
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