Because of the sporadic release of GH, the patient will have his blood drawn a total of five times over a few hours. Instead of the traditional method of blood drawing (veinipuncture), the blood is taken through an IV (angiocatheter).
How to prepare for the test:
You should fast and limit physical activity for 10 to 12 hours before the test. If you are taking certain medications, your health-care provider may ask that you withhold these before the test, as some can affect results.
You will be asked to relax for at least 90 minutes before the test, as exercise or increased activity can alter hGH levels. Inform your health-care provider if you or your child has had a radioactive scan performed within a week of this test, as radioactive scans can affect test results.
If your child is to have this test performed it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll. This test requires temporary placement of an angiocatheter, an IV, and this should be explained to your child. The more familiar your child is with what will happen to him, and the purpose for the procedure, the less anxiety he will feel. How the test will feel: When the needle is inserted, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
What the risks are:
Risks associated with venipuncture are slight:
- excessive bleeding fainting or
- feeling lightheaded hematoma (blood accumulating under the skin)
- infection (a slight risk any time the skin is broken)
- multiple punctures to locate veins
- clinical signs and symptoms of hypoglycemia if IV insulin is administered.
Update Date 5/10/2014
Updated by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial Team.