Growth Hormone Stimulation Test (Outpatient)

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Growth Hormone Stimulation Test (Outpatient)

A growth hormone stimulation test is done to find out if the pituitary gland is releasing growth hormone (GH) in the right amounts. The pituitary is a small gland in the brain about the size of a pea; it releases hormones into the bloodstream that affect growth. Medicine will be used to stimulate the pituitary gland to release growth hormone into the blood.

The medicines used with your child are L-arginine (L-AR-jah-neen) and:

  • Clonidine (KLON-uh-deen)
  • Glucagon (GLU-ka-gon)

Samples of blood are then taken and sent to the laboratory. In the lab, the growth hormone levels in the blood are measured.

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 go to bed at the usual time.
  • 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.
  • Be sure to tell the doctor if your child has any allergies or reactions to medicine, food preservatives or dyes. Make sure to tell the doctor about the allergy and how it affected your child. This includes telling about rash, hives, itching, shortness of breath, wheezing, coughing, swelling of face, lips, tongue or throat or any other symptoms involved.

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 and a VCR, so feel free to bring a favorite movie. Bring a snack for your child to eat after the test.

How the test is done

Image of growth hormone stimulation test

Picture 1: Having a growth hormone stimulation test

The test will be done in the Infusion Clinic (see Picture 1). It takes about 3 hours and 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 IV (intravenous line). A sample of blood will be drawn from the IV. The IV will be used to draw blood samples and give the L-Arginine.
  • The first medicine given is clonidine or glucagon. Clonidine is a pill that is taken by mouth. Glucagon is another medicine, given by injection just under the skin in the upper arm. Blood is drawn every 30 minutes for an hour.
  • The L-Arginine is given 1 hour after the clonidine. The L-Arginine solution will be put into the IV during a 30-minute period. The IV is left in place so no other IV’s will be needed to draw blood samples.
  • Blood samples will be drawn for growth hormone studies every 30 minutes for 3 hours. Your child will not feel any discomfort when the blood samples are drawn. The total amount of blood is small (about 3-1/2 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.

  • Have your child drink plenty of liquids the rest of the day.
  • Your child should not attend school and should not take part in any sports or exercise, especially swimming, for the rest of the day.
  • Your child's doctor will contact you about the test results and plan for medical care.

Side effects of medicines

Clonidine: Because clonidine lowers blood pressure, the most common side effect is feeling dizzy and lightheaded. Children should rise slowly after sitting or lying down and be extra careful climbing stairs. Your child may also feel very sleepy for a few hours or have dry mouth, dry eyes or blurry vision. These side effects can last up to 24 hours and your child should avoid activities that require alertness or clear vision. Your child should be fine the following day after a good night’s sleep.

L-Arginine: This medicine can cause low blood sugar, which can also lead to lightheadedness or nausea. Side effects from L-Arginine are rare and usually pass by the time your child goes home.

Glucagon: This medicine can also cause low blood sugar which can lead to nausea and vomiting. After the test has been completed, a snack or meal will help to make your child feel better.

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 Tower elevators to level 4 and turn left into Suite D.

Three parking options are available:

  • Park in the Hospital Garage on Children’s Drive. Once inside, turn right and follow the Blue Path until it meets the Green Path at the Crossroads Registration Area.
  • Park in the Outpatient Care Garage on 18th Street. Follow the Blue Path until it meets the Green Path at the Crossroads Registration Area.
  • Use the valet parking on Children’s Drive or 18th Street. Follow the Blue Path until it meets the Green Path at the Crossroads Registration Area.

*You will be required to stop at the security desk before you enter the elevator.

If you have any questions, be sure to ask your doctor or nurse.

Growth Hormone Stimulation Test (Outpatient) (PDF)

HH-III-15 Revised 3/15 Copyright 2010, Nationwide Children's Hospital 

Nationwide Children's Hospital
700 Children's Drive Columbus, Ohio 43205 614.722.2000