Growth hormone test

GH test

The growth hormone test measures the amount of growth hormone in the blood.

The pituitary gland makes growth hormone, which causes a child to grow. This gland is located at the base of the brain.

How the Test is Performed

How to Prepare for the Test

Your health care provider 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. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

This hormone may be checked if a person's growth pattern is abnormal or if another condition is suspected.

Too much growth hormone (GH) can cause abnormally increased growth patterns. In adults, this is called acromegaly. In children, it is called gigantism.
Acromegaly
Acromegaly is a condition in which there is too much growth hormone (GH) in your body.
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Gigantism
Gigantism is abnormal growth due to an excess of growth hormone (GH) during childhood.
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Too little growth hormone can cause a slow or flat rate of growth in children. In adults, it can sometimes cause changes in energy, muscle mass, cholesterol levels, and bone strength.
Too little growth hormone
Growth hormone deficiency means the pituitary gland does not make enough growth hormone.
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The GH test may also be used to monitor response to acromegaly treatment.

Normal Results

The normal range for GH level is typically:

For adult males -- 0.05 to 3 nanograms per milliliter (ng/mL)
For adult females -- 0.05 to 8 ng/mL
For children -- varies with age and sex, ask your provider what is normal for your child

GH is released in pulses. The size and duration of the pulses varies with time of day, age, and sex. This is why random GH measurements are rarely useful. 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. GH is most useful when measured as part of a stimulation or suppression test.

Normal value ranges may vary slightly among different labs. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

A high level of GH may indicate:

Acromegaly in adults. (A special test must be done to confirm this diagnosis.)
Special test
The growth hormone suppression test determines whether growth hormone (GH) production can be suppressed by taking a specific amount of glucose (calle...
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Gigantism in children. This is abnormal growth due to excess GH. (A special test must be done to confirm this diagnosis.)
GH resistance.
Pituitary tumor.
Pituitary tumor
A pituitary tumor is an abnormal growth in the pituitary gland. The pituitary is a small gland at the base of the brain. It regulates the body's ba...
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A low level of GH may indicate:

Slow growth noticed in infancy or childhood. (A special test must be done to confirm this diagnosis.)
Hypopituitarism (low function of the pituitary gland). The pituitary gland makes several hormones besides GH and these may be low as well.
Hypopituitarism
Hypopituitarism is a condition in which the pituitary gland does not produce normal amounts of some or all of its hormones.
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Risks

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person 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 lightheaded
Lightheaded
Dizziness is a term that is often used to describe 2 different symptoms: lightheadedness and vertigo. Lightheadedness is a feeling that you might fai...
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Multiple punctures to locate veins
Hematoma (blood buildup under the skin)
Hematoma
A bruise is an area of skin discoloration. A bruise occurs when small blood vessels break and leak their contents into the soft tissue beneath the s...
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Infection (a slight risk any time the skin is broken)

Open References

References

Ali O. Hyperpituitarism. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 598.

Divall SA, Radovick S. Normal and aberrant growth in children. In: Melmed S, Auchus RJ, Goldfine AB, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 22.

Kaiser U, Ho KKY. Pituitary physiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 6.

Weiss RE. Anterior pituitary. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 205.

Growth hormone stimulation test - series
Presentation

<strong>Growth hormone stimulation test - series</strong><p>The growth hormone (GH) is a protein hormone released from the anterior pituitary gland under the control of the hypothalamus. In children, GH has growth-promoting effects on the body. It stimulates the secretion of somatomedins from the liver, which are a family of insulin-like growth factor (IGF) hormones. These, along with GH and thyroid hormone, stimulate linear skeletal growth in children. In adults, GH stimulates protein synthesis in muscle and the release of fatty acids from adipose tissue (anabolic effects). It inhibits uptake of glucose by muscle while stimulating uptake of amino acids. The amino acids are used in the synthesis of proteins, and the muscle shifts to using fatty acids as a source of energy. GH secretion occurs in a pulsatile (short, concentrated secretion) and sporadic manner. Thus, a single test of the GH level is usually not performed.</p>

<strong>Indications</strong><p>Why the test is performed. This test is typically performed on infants and children to identify human growth hormone (hGH) deficiency as a cause of growth retardation. It can be useful in detecting some types of pituitary tumors.</p>

<strong>Procedure</strong><p>Because of the sporadic release of GH, the patient will have his blood drawn a total of five times over a few hours. Instead of the traditional method of blood drawing (veinipuncture), the blood is taken through an IV (angiocatheter). How to prepare for the test. You should fast and limit physical activity for 10 to 12 hours before the test. If you are taking certain medications, your health-care provider may ask that you withhold these before the test, as some can affect results. You will be asked to relax for at least 90 minutes before the test, as exercise or increased activity can alter hGH levels. If your child is to have this test performed it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll. This test requires temporary placement of an angiocatheter, an IV, and this should be explained to your child. The more familiar your child is with what will happen to him, and the purpose for the procedure, the less anxiety he will feel. How the test will feel. When the needle is inserted, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing. Risks associated with venipuncture are slight and may include excessive bleeding fainting or feeling lightheaded hematoma (blood accumulating under the skin), infection (a slight risk any time the skin is broken), multiple punctures to locate veins, clinical signs and symptoms of hypoglycemia if IV insulin is administered.</p>

<strong>Results</strong><p>What abnormal results mean. A diminished amount of hGH indicates a problem either in the hypothalamus or the pituitary. Additional testing can illustrate the exact site of the deficiency. In children, a deficiency of GH results in dwarfism. In adults, it may be associated with panhypopituitarism. About 10% to 15% of people with normal functioning pituitaries may fail to respond on the first test. The test is often repeated.</p>

Growth hormone stimulation test - series
Presentation

A Closer Look

Self Care

Tests for Growth hormone test

Review Date: 1/25/2026

Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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Health Library

Growth hormone test

How the Test is Performed

Blood sample

How to Prepare for the Test

How the Test will Feel

Why the Test is Performed

Acromegaly

Gigantism

Too little growth hormone

Normal Results

What Abnormal Results Mean

Special test

Pituitary tumor

Hypopituitarism

Risks

Lightheaded