A growth hormone stimulation test measures how well the pituitary gland makes growth hormone. The pituitary gland is part of the body’s endocrine system. Growth hormone helps control how the body grows and how it uses nutrients from food, such as glucose (sugar) for energy. Your child needs growth hormone for normal growth and development.
Growth hormone stimulation testing can help diagnose growth hormone deficiency (GHD), a condition where the body does not make enough growth hormone.
During the test, your child will get medicines to stimulate the pituitary gland. Your child will provide several blood samples over a set time period. The blood samples will be tested to see how much growth hormone released.
How to prepare for a growth hormone stimulation test
Follow your care team's instructions on how to prepare for the test.
Your child will need to follow fasting guidelines or NPO instructions for when to stop eating and drinking. At the specified time before the test (generally 8 hours), stop giving your child solid food, enteral (tube) feeds, and liquids. They can continue to drink water.
Give your child their usual medicine the morning of the test unless the care team tells you not to do so.
Have your child wear comfortable clothes. Bring activities such as books, games, or tablets that your child can do during the test.
What to expect during growth hormone stimulation testing
You can stay with your child during the growth hormone stimulation test. Before the test, the care team will place an IV in a vein in your child’s arm. The test lasts about 4–5 hours.
Common medications used during growth hormone stimulation tests include:
Arginine: Your child will get arginine through the IV. Arginine is a substance that the body uses to make proteins.
Glucagon: Your child will get an injection (shot) of glucagon under the skin in the upper arm. Glucagon is a hormone that controls blood sugar levels.
Carbidopa-levodopa: Your child will take a pill called carbidopa-levodopa. This medicine helps the body to produce growth hormone.
The care team will usually give one of these common medication combinations during the test. During the test, the care team will draw small blood samples through the IV for testing in the lab. The nurse will also check your child’s vital signs and blood sugar levels.
At the end of the test, the nurse will remove the IV. Your child will have a snack.
After the growth hormone stimulation test
Your child may be hungry. They can eat and drink normally after the test.
For the rest of the day, your child should rest and avoid too much activity. They should avoid standing up or lying down too quickly.
Your child will be able to return to normal activities the next day.
Possible side effects of a growth hormone stimulation test
The medicines used in the test can cause side effects. These are usually mild and temporary. Side effects may include:
Childhood cancer survivors who had certain cancers and treatments affecting the pituitary gland may have a growth hormone deficiency. This condition should be managed by an endocrinologist.
Your child may need to stop eating and drinking before certain medical tests or procedures. Learn about fasting guidelines, also called NPO instructions.
