Growth Hormone (GH)

In children, GH plays a major role in bone growth, muscle mass development, and height. In adults, GH affects bone and muscle health. If you or your child have too much or too little GH, it can cause health problems. In children, GH testing is also used to investigate short stature and to help tell low GH production apart from other causes of slow growth.

GH levels in your blood change throughout the day, depending on your diet and activity levels. So, a standard blood test doesn't usually provide helpful information about GH levels. Instead, GH levels are usually checked in blood tests taken over a few hours that measure other substances, such as proteins and other hormones that are related to GH production. Stimulation and suppression tests, which check how your GH levels respond to certain triggers, are often more helpful than a single random measurement.

GH levels in the blood vary throughout the day, so a single random GH measurement is generally not enough to diagnose acromegaly or GH deficiency. Instead, providers usually rely on a combination of tests.

If GH levels don't increase to a certain level during a GH stimulation test, it may mean that there is a GH deficiency.

If your child is diagnosed with GH deficiency, they may benefit from treatment with GH supplementation. GH supplementation is an injected medicine that contains manufactured human growth hormone. When GH deficiency is diagnosed and treated early, some children can grow several inches in the first year of treatment. Others grow less and more slowly but still benefit from treatment.

If GH levels don't decrease to a certain level during a GH suppression test (typically after drinking a glucose drink), and IGF-1 is also high, it may mean that there is a GH excess. For your child, this could mean they have gigantism. For you, it may mean you have acromegaly. A single GH blood test by itself is not used to diagnose acromegaly.

Gigantism and acromegaly are most often caused by a tumor in the pituitary gland. Treatment for the tumor may include radiation therapy, surgery, and/or medicine. But if the cause is not a tumor, you or your child may need more tests to identify the cause.