Adrenocorticotropic Hormone (ACTH) Test

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The Adrenocorticotropic Hormone (ACTH) test is an essential medical tool that helps doctors understand various health conditions. Let's break down the key aspects of this test in simple and easy-to-understand terms.


What is it used for?

The ACTH test evaluates the concentration of adrenocorticotropic hormone in your bloodstream. ACTH is produced by the pituitary gland, a small gland located at the base of your brain. This hormone plays a crucial role in stimulating the adrenal glands to release cortisol, a hormone that helps manage stress, regulate metabolism, and maintain blood pressure.

Doctors use the ACTH test to diagnose and monitor conditions related to abnormal cortisol levels, such as:

  • Addison's disease (low cortisol production)
  • Cushing's syndrome (high cortisol production)
  • Pituitary gland disorders
  • Adrenal gland disorders

Why do I need an ACTH test?

An ACTH test may be necessary if you exhibit symptoms indicating that your cortisol levels are abnormally high or low. 

Symptoms of high cortisol levels include weight gain, high blood pressure, muscle weakness, and changes in skin appearance. 

Symptoms of low cortisol levels include fatigue, weight loss, low blood pressure, and darkening of the skin.

Additionally, if you have been diagnosed with an adrenal or pituitary disorder, your doctor might order this test to monitor your condition and treatment effectiveness.

What happens during an ACTH test?

The ACTH test is a simple blood test. Here’s what you can expect:

Preparation: You might be asked to fast (not eat or drink anything except water) for a few hours before the test. This ensures that the test results are accurate.

Blood Draw: A healthcare professional will clean a small area of your arm and insert a needle into a vein to draw a blood sample. This procedure typically lasts only a brief span of minutes.

Aftercare: Once the blood sample is taken, you can resume your normal activities. The sample is sent to a lab for analysis.

Do I need to prepare for the test in any way?

Preparation for the ACTH test is usually straightforward. Your doctor might give you specific instructions, such as fasting for a few hours before the test. It's important to follow these instructions to ensure the test results are accurate. Also, inform your doctor about any medications or supplements you are taking, as some can affect the test results.

Are there any risks to the test?

The ACTH test is generally safe with minimal risks. Some people might experience:

  • Minor discomfort or bruising may occur at the site where blood is drawn.
  • Dizziness or fainting (rarely)

These side effects are usually mild and temporary. If you have any concerns, discuss them with your healthcare provider before the test.

What do the results mean?

The results of your ACTH test can provide valuable insights into your health:

  • High ACTH levels: May indicate conditions like Addison's disease, Cushing's disease, or an ectopic ACTH-producing tumor.
  • Low ACTH levels: May suggest conditions like secondary adrenal insufficiency or adrenal tumors.

Your doctor will interpret the results in the context of your symptoms, medical history, and other tests. They will discuss the findings with you and explain what the results mean for your health.


Are there any other important details I should be aware of regarding the ACTH test?

It's important to keep in mind that the ACTH test is just one piece of the puzzle. Your doctor might order additional tests to confirm a diagnosis or get a complete picture of your health. Regular follow-up appointments and tests might be necessary to monitor your condition and adjust treatment as needed.


The ACTH test is a valuable tool for diagnosing and managing conditions related to cortisol levels. Understanding why the test is needed, what to expect, and how to interpret the results can help you feel more prepared and informed. If you have any questions or concerns about the ACTH test, don’t hesitate to talk to your healthcare provider. They are there to guide you through the process and ensure you receive the best care possible.