ACTH Stimulation Test (for CAH)

Specimen Required

3 Clotted Blood and 1 EDTA

Fasting Required

Purpose of the Test

The ACTH stimulation test is used to evaluate adrenal gland function and diagnose CAH, specifically 21-hydroxylase deficiency, the most common form of CAH. This condition affects the adrenal glands’ ability to produce cortisol and can lead to excess production of androgens, which can cause a variety of symptoms, including ambiguous genitalia in newborns, precocious puberty, and infertility in females.

When this test is required

The ACTH stimulation test may be requested when a newborn is born with ambiguous genitalia, which may suggest a genetic disorder affecting the adrenal glands. The test may also be ordered when a child or adult presents with symptoms of CAH, such as early onset of puberty or irregular menstrual periods.

What the Test Detects

The ACTH stimulation test measures the adrenal gland’s ability to produce cortisol in response to adrenocorticotropic hormone (ACTH). The test is used to diagnose certain types of congenital adrenal hyperplasia (CAH), a group of genetic disorders that affect the adrenal glands.

Preparation for the Test

There are several preparation steps necessary for the ACTH stimulation test. A healthcare provider will provide specific instructions, but preparation may include fasting for a certain amount of time prior to the test, avoiding certain medications that may interfere with the test, and avoiding strenuous exercise. It is important to inform your healthcare provider of any medications you are taking or medical conditions you have that may affect the test results. It is also important to inform your healthcare provider if you have any allergies or bleeding disorders.

Sample Requirements

The ACTH stimulation test requires a blood sample. The test is performed in two stages. In the first stage, a baseline blood sample is taken to measure the levels of cortisol and other hormones in the blood. In the second stage, a synthetic form of adrenocorticotropic hormone (ACTH) is injected, and additional blood samples are taken to measure the body’s response to the hormone.

Additional Notes

The ACTH stimulation test is typically performed in two stages. In the first stage, a baseline blood sample is taken to measure the levels of cortisol and other hormones in the blood. In the second stage, a synthetic form of adrenocorticotropic hormone (ACTH) is injected, and additional blood samples are taken to measure the body’s response to the hormone. It is important to follow your healthcare provider’s instructions carefully to prepare for the test, which may include fasting for a certain amount of time prior to the test, avoiding certain medications that may interfere with the test, and avoiding strenuous exercise. It is also important to inform your healthcare provider of any medications you are taking or medical conditions you have that may affect the test results. After the test, your healthcare provider will review the results with you and determine if additional testing or treatment is necessary.

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