The growth hormone (GH) stimulation test measures the level of growth hormone (GH) in the blood after you receive medication that triggers the release of GH, such as arginine or GH-releasing hormone. The test measures the ability of the pituitary gland to release GH.
In Apollo Children’s Hospital, we perform Growth Hormone stimulation testing with clonidine and with glucagon.
Clonidine stimulation testing for Growth Hormone:
In this testing, Clonidine is given orally and Growth hormone is tested every 30minutes. This testing is done under observation for a period of 2 hours. The results are available on the same day. Blood pressure may go low during the procedure.
Glucagon Stimulation testing for Growth Hormone:
In this testing, Glucagon injection is give im and Growth hormone is tested every 30minutes. This testing is also done under observation for a period of 3 hours. The results are available on the same day.
How the Test is Performed
Blood is drawn several times. Blood samples are taken through an intravenous (IV) line instead of re-inserting the needle each time. The test takes between 2 to 5 hours.
How to Prepare for the Test
DO NOT eat for 10 to 12 hours before the test. Eating food can change the test results. Some medicines can affect the test results. Ask your pediatric endocrinologist if you should stop taking any of your medicines before the test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. These soon go away.
Why the Test is Performed
This test is most often done to either confirm or exclude growth hormone deficiency in a child with short stature.
Normal results include:
Normal peak value, at least 10 nanogram per milliliter (ng/mL)
Indeterminate, 5 to 10 ng/mL
Subnormal, 5 ng/mL
(A normal value rules out hGH deficiency)
Normal value ranges may vary slightly among different laboratories. Hence, we recommend doing GH stimulation testing in Apollo Hospitals.
What Abnormal Results Mean
If this test does not raise GH levels, there is a reduced amount of hGH stored in the anterior pituitary. In children, this results in GH deficiency and cause severe short stature. In adults, it may be linked to panhypopituitarism or adult GH deficiency.