Growth Hormone Tests

Growth hormone (GH) tests are blood tests that check if your body is making a normal amount of GH. Hormones are chemical messengers in your bloodstream that control the actions of certain cells or organs. GH, also known as human growth hormone, controls your body's growth.

It also helps control metabolism, the process your body uses to make energy from the food you eat. GH is made in the pituitary gland, a small organ at the base of your brain that controls many functions, including growth. 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. 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. This will provide more accurate results about your or your child's GH levels.

Why this test is done

Your provider may order a GH test if you or your child has symptoms of a GH disorder or to monitor treatment for a GH disorder.

Symptoms of GH deficiency in children include:

• Slowed growth rate compared with children of the same age and sex
• Shorter height, arms, and legs, and lower weight than children of the same age and sex
• Small penis in males
• Delayed puberty

Adults with GH deficiency may have symptoms such as fatigue and decreased bone density and muscle mass. But GH testing isn't common for adults, as other disorders are much more likely to cause these symptoms.

Symptoms of GH excess (gigantism) in children include:

• Excessive growth compared with children of the same age and sex
• Overly large head
• Larger than normal hands and feet
• Mild to moderate obesity

Symptoms of GH excess (acromegaly) in adults include:

• Deep, husky voice
• Larger than normal facial features such as lips, nose, and tongue
• Excessive sweating and body odor
• Thickening of bones
• Coarse, oily skin
• Irregular menstrual cycles in women
• Erectile dysfunction in men

How to prepare

You may need to fast (not eat or drink) for several hours before your test.

Sample type

Blood

Other names for this test

GH test, human growth hormone test, somatotropin test, growth hormone stimulation test, growth hormone suppression test