ACTH stimulation test

What is an ACTH Stimulation Test?

An ACTH stimulation test is a procedure used to measure the amount of adrenocorticotropic hormone (ACTH) in a person’s body. This hormone is produced by the pituitary gland and stimulates the adrenal glands to produce cortisol. Cortisol is a steroid hormone that helps to regulate blood glucose levels, suppress inflammation, and respond to stress.

Preparation for the ACTH Stimulation Test

The preparatory steps for the ACTH stimulation test are quite straightforward. You will need to avoid caffeine and alcohol 24 hours before the test. You must also fast (unless your doctor says otherwise). This means avoiding food and drinks (except water) for 8-12 hours prior to the test.

Procedure of the ACTH Stimulation Test

The procedure begins with a blood sample being taken from your arm. This helps the doctor determine your baseline level of cortisol. After the sample is sent to the lab, the next step is for the doctor to administer a synthetic form of ACTH (sometimes known as cosyntropin) into your body typically via an injection. A second blood sample is taken 30-45 minutes from receiving the injection to measure the cortisol levels in the blood post-injection.

Types of ACTH Stimulation Tests

There are two types of the ACTH stimulation test:

  • The Synacthen Test – This test focuses on the stimulation and assessment of the patient's adrenal glands.
  • The Cortrosyn Test – This test involves the assessment of the cortisol production from the adrenal glands.

Risks of ACTH Stimulation Test

The risks associated with the ACTH stimulation test are considered minimal. However, they do include dizziness, headache, nausea, and anxiety.

Why is an ACTH Stimulation Test Done?

The ACTH stimulation test is typically used to diagnose certain types of adrenal problems. These include adrenal insufficiency, Addison’s disease, Cushing’s syndrome, and other diseases. It may also be used to diagnose pituitary problems or to check on possible side effects of medications.

When to Get an ACTH Stimulation Test?

An ACTH stimulation test may be prescribed to you if the doctor suspects that you may have Addison’s disease or any other form of adrenal insufficiency. If observing your symptoms or a basic physical exam does not give any clear indication as to the cause of the problem, the ACTH stimulation test may be ordered.