Arginine test
Key points
- The growth hormone (GH) stimulation test measures the plasma level of human growth hormone (hGH) after the administration of the amino acid arginine and/or GH-releasing hormone.
- An angiocatheter (IV) is usually placed in a vein, typically in the inside of the elbow or the back of the hand.
- You will be asked to fast and limit physical activity for 10 to 12 hours before the test, or test results may be altered and invalidated.
- When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation.
Alternative names
Growth hormone stimulation test
Definition
The growth hormone (GH) stimulation test measures the plasma level of human growth hormone (hGH) after the administration of the amino acid arginine and/or GH-releasing hormone. It measures the ability of the pituitary to secrete GH.
How the test is performed
An angiocatheter (IV) is usually placed in a vein, typically in the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band or blood pressure cuff is placed around the upper arm to cause the veins below the band to swell with blood.
A needle is inserted into the vein, and then removed while the angiocatheter is left in the vein. The band is then removed to restore circulation.
Your blood will be drawn 5 times. To prevent multiple punctures of the vein, samples will be taken through the IV line instead of repeatedly re-inserting the needle.
The first sample will be drawn between 6 a.m. and 8 a.m., then an intravenous (IV) infusion of arginine is started and continued for 30 minutes. After the 30-minute infusion, GH-releasing hormone is administered intravenously and then four more blood samples are drawn at 30-minute intervals.
(Sometimes arginine or GH-releasing hormone is given alone for this test. The variation of the test used depends on the preferences of the prescribing physician.)
How to prepare for the test
You will be asked to fast and limit physical activity for 10 to 12 hours before the test, or test results may be altered and invalidated.
If you are taking medications, your health care provider may ask that you withhold these before the test, as some can affect results. (Do not discontinue any medications without checking with your health care provider.)
You will be asked to relax for at least 90 minutes before the test, as exercise or increased activity can alter hGH levels.
If your child is to have this test performed, it may be helpful to explain how the test will feel. You may want to practice or demonstrate on a doll. This test requires temporary placement of an IV, and you should explain this to your child. The more familiar your child is with what will happen and the purpose for the procedure, the less anxiety he or she will feel.
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a bruise may develop at the site where the needle was inserted. These symptoms are temporary.
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.