Growth Hormone

Human Growth Hormone (hGH), Somatotropin

What To Think About

• Normal levels of growth hormone (GH) change during the day so other tests may be done to confirm the results of a GH test. Other tests can show whether low levels of GH (which can be normal) mean the pituitary gland is not working correctly.
  • Insulin-like growth factor 1 (IGF-1) blood levels are often done at the same time as a GH test. A high level of IGF-1 with a high level of GH generally means acromegaly is present. In this case, magnetic resonance imaging (MRI) is done to look at the pituitary gland. For more information, see the medical test Magnetic Resonance Imaging (MRI) of the Head.
  • The growth hormone suppression test (also called the glucose loading test) measures the level of GH in the blood before and after a person drinks fluid with a large amount of sugar (glucose) in it. Normally, the amount of GH drops to less than 1 ng/mL after drinking the glucose. Levels of GH that stay high may mean acromegaly is present.
  • The growth hormone stimulation test (also called the insulin tolerance test) measures the level of GH in the blood before and after insulin is given in a vein (intravenously) in the arm. Growth hormone levels of 0 µg/L (0 ng/mL) can be found in people who lack GH as well as in people with normal pituitary function. A growth hormone stimulation test may be used to see if a person lacks GH. Normally, the amount of GH increases after insulin causes the blood sugar to drop (in children, the level should be more than 10 µg/L [10 ng/mL]; in adults, it should be more than 7 µg/L [7 ng/mL]). A GH level that does not increase after the insulin is given may mean the person lacks growth hormone.

Go to previous section	Go to top of page	Go to next section
Author:	Douglas Dana Jan Nissl, RN, BS	Last Updated: December 1, 2006
Medical Review:	Adam Husney, MD - Family Medicine Caroline S. Rhoads, MD - Internal Medicine David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism
© 1995-2008 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.