Growth Hormone Test

Why am I having this test?

The growth hormone test is used to check for growth hormone levels that are too low or too high. This hormone promotes normal growth from birth through the end of puberty. The test is often done on adolescents who are shorter than expected, have delayed sexual maturity, or have other growth deficiencies. It may also be used to confirm the diagnosis of increased bone size (gigantism or acromegaly).

What is being tested?

This test measures the amount of growth hormone in your blood to determine how much your body is producing. Growth hormone is made by the pituitary gland, which is a small organ located at the bottom of the brain.

What kind of sample is taken?

A blood sample is required for this test.

How do I prepare for this test?

Make sure you get enough sleep before this test and are well rested.
Try to avoid being emotionally or physically stressed when you have your blood drawn for this test. Stress can affect growth hormone levels.
Do not eat or drink anything except water after midnight on the night before the test or as told by your health care provider.
Ask your health care provider about changing or stopping your regular medicines before the test. Ask your health care provider if you need to avoid taking certain medicines before the test.

Tell a health care provider about:

Any allergies you have.
All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
Any blood disorders you have.
Any surgeries you have had.
Any medical conditions you have.
Whether you are pregnant or may be pregnant.

What happens during the test?

You will have a blood sample taken from a vein in your arm.

How are the results reported?

Your test results will be reported as values. Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:

Men: Less than 5 ng/mL or less than 5 mcg/L (SI units).
Women: Less than 10 ng/mL or less than 10 mcg/L (SI units).
Children:
- Newborn: 5–23 ng/mL or 5–23 mcg/L (SI units).
- 1 week old: 2–27 ng/mL or 2–27 mcg/L (SI units).
- 1–12 months old: 2–10 ng/mL or 2–10 mcg/L (SI units).
- Females older than 1 year: 0–10 ng/mL or 0–10 mcg/L (SI units).
- Males older than 1 year: 0–6 ng/mL or 0–6 mcg/L (SI units).

What do the results mean?

Abnormally high levels of growth hormone may indicate problems such as:

Gigantism.
Acromegaly.
Anorexia nervosa.
Chronic or high levels of stress.
Major surgery.
Hypoglycemia.
Starvation.

Abnormally low levels of growth hormone may indicate problems such as:

Growth hormone deficiency.
Pituitary gland malfunction (pituitary deficiency).
Dwarfism.
Hyperglycemia.
Failure to thrive.
Delayed sexual maturity.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

When will my results be ready?
How will I get my results?
What are my treatment options?
What other tests do I need?
What are my next steps?

Summary

The growth hormone test is used to check for growth hormone levels that are too low or too high.
This test is often done on adolescents who are shorter than expected, have delayed sexual maturity, or have other growth deficiencies. It is also used to confirm the diagnosis of increased bone size (gigantism or acromegaly).
A blood sample is required for this test.
Talk with your health care provider about what your results mean.