Congenital Adrenal Hyperplasia (CAH) Stimulation Test

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What is a congenital adrenal hyperplasia (CAH) stimulation test?

The congenital adrenal hyperplasia (CAH) stimulation test shows how well your child’s adrenal glands produce hormones. Hormones are substances made by the body that affect many body functions.

The adrenal glands, located just above the kidneys, respond to a hormone known as adrenocorticotropic hormone (ACTH), which causes them to release more hormones. ACTH comes from a small gland near the brain called the pituitary.

How to prepare for the test

Your child can eat and drink as usual before the test. Give your child their usual medicine(s) on 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 they can use during the test.

Illustration of cortisol going through hypothalamus, pituitary gland, and adrenal gland — A part of the brain called the hypothalamus releases a hormone called CRH. This hormone makes the pituitary gland near the brain release another hormone, called ACTH. ACTH makes the adrenal glands release hormones such as cortisol, which affect body functions.

Congenital adrenal hyperplasia (CAH)

CAH may be found during routine screening tests that check newborns for disease. More testing may be needed to see if they have a problem that is passed down (inherited) from their parents that causes CAH.

Children with CAH may have changes to their genes (DNA). These changes affect how well their bodies make hormones. Their hormones may not work as they should, so they may have problems with:

Cortisol or stress hormone levels
Salt levels
The appearance of genitals in females
Early signs of sex hormones, like pubic hair or enlargement of the genitals before the usual age
Fertility (ability to produce children)

The disorder has 2 main types: classic CAH and nonclassic CAH.

Classic CAH is the more severe type. It is often diagnosed at birth.
Nonclassic CAH is usually diagnosed later and is more common than the classic type. The symptoms of nonclassic CAH are often milder than those of the classic type.

What to expect during the test

You can stay with your child during the test. Before the test, the care team will place an IV in your child’s arm.

The team will give a medicine known as cosyntropin through the IV. This medicine acts like the ACTH hormone and causes your child’s adrenal glands to release more hormones.
The care team will draw blood samples through the IV for testing in the lab.
A nurse will check your child’s vital signs during the test.
At the end of the test, the nurse will remove the IV.

Possible risks or side effects

Your child should not have any side effects from the test.

After the test

Your child can return to normal activities after the test.

Key points about the CAH stimulation test

A congenital adrenal hyperplasia (CAH) stimulation test measures how well the body’s adrenal glands work to produce hormones.

Doctors use this test to help diagnose CAH.
In this test, your child gets medicines that cause the adrenal glands to release hormones.
The nurse will take blood samples to measure the amounts of hormones released over time.
Your child should not have any side effects from the test and should be able to return to normal activities the same day.

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Reviewed: August 2023