The growth hormone test measures the amount of growth hormone in the blood.
How the test is performed
A blood sample is needed. For information on how this is done, see:
How to prepare for the test
Your doctor may give you special instructions about what you can or cannot eat before the test.
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.
Why the test is performed
Growth hormone is released from an area just below the brain called the anterior pituitary gland.
- Too much growth hormone can cause abnormal growth patterns called
acromegalyin adults and gigantismin children.
- Too little growth hormone can cause
a slow or flat rate of growthin children, and changes in muscle mass, cholesterol levels, and bone strength in adults.
The growth hormone test may be used to monitor response to acromegaly treatment.
Different tests are used to diagnose growth problems:
- GHRH or GHRH-arginine stimulation (to help diagnose a lack of growth hormone)
Growth hormone stimulation test
- IGF-1 levels
- Oral glucose tolerance suppression (to help diagnose too much growth hormone)
The normal range for growth hormone levels is typically:
- 1 – 9 ng/mL (male)
- 1 – 16 ng/mL (female)
GH is released in pulses. A higher level may be normal if the blood was drawn during a pulse. A lower level may be normal if the blood was drawn around the end of a pulse.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
High levels of growth hormone may indicate:
- Growth hormone resistance
Low levels of growth hormone may indicate:
- Growth hormone deficiency
Hypopituitarism(low function of the pituitary gland)
What the risks are
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)