Test Overview
A growth hormone (GH) test measures the amount of human growth
hormone (GH) in the blood. GH is made by the
pituitary gland and is needed for growth. It
plays an important role in how the body uses food for energy (metabolism). The amount of GH in the blood changes
during the day and is affected by exercise, sleep, emotional stress, and
diet.
Too much GH during childhood can cause a child to grow larger than normal (gigantism). Too little GH during childhood can cause a child to grow smaller than normal (dwarfism). Both conditions can be
treated if found early.
In adults, too much GH is caused by a noncancerous tumor of
the pituitary gland
(adenoma). Too much GH can cause bones of the face, jaw, hands, and feet to grow larger than normal (acromegaly).
Growth hormone can cause the release of other substances (factors)
that affect growth and
metabolism. One of these is
insulin-like growth factor 1 (IGF-1). When the GH
level is very high, the IGF-1 level is also very high. A test for
IGF-1 may also be done to confirm high GH
levels.