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ACTH Stimulation Blood Test

Last updated May 26, 2018

Approved by: Krish Tangella MD, MBA, FCAP

The ACTH Stimulation Blood Test involves the administration of syntropin in various doses and observation of pituitary gland hormonal release.

What are other Names for this Test? (Equivalent Terms)

  • ACTH Stimulation Blood Levels Test
  • Adrenocorticotropic Hormone Stimulation Blood Test
  • Cosyntropin Blood Test

What is ACTH Stimulation Blood Test? (Background Information)

  • ACTH stands for adrenocorticotropic hormone. ACTH is produced in the pituitary gland, which is situated just below the brain. Cosyntropin is another name for artificial ACTH and it has the same potency as natural ACTH
  • ACTH stimulates the adrenal glands to produce hormones. These include stress hormones such as adrenaline, also called epinephrine, and cortisol. The adrenal glands are small, pyramid-shaped organs located above each kidney
  • Adrenaline causes a number of effects that help the body respond to stress. These effects include increased heart rate and breathing, increased muscle contraction, and increased fat breakdown for energy
  • Cortisol is another stress hormone produced by the adrenal glands in response to ACTH. One effect of cortisol is to increase energy availability. It does this by stimulating the liver to produce glucose. It also does this by stimulating fat cells to release fatty acids into blood for immediate use. Another effect of cortisol is to suppress inflammation. It does this by inhibiting the effects of white blood cells and other components of the immune system
  • In addition to stress hormones, the adrenal glands also produce hormones that regulate electrolyte levels. These hormones include aldosterone. Electrolytes are necessary for a variety of functions, including maintaining hydration status and blood pressure
  • ACTH itself is stimulated by another hormone called CRH, or corticotropin-releasing hormone. CRH is produced in the hypothalamus of the brain
  • After ACTH causes the adrenal gland to release its various hormones, these hormones act back on the pathway, on the hypothalamus and pituitary gland, to prevent further release of hormones. This is known as negative feedback
  • The ACTH Stimulation Blood Test involves the administration of syntropin in various doses and observation of pituitary gland hormonal release. It is used to diagnose defects in the hypothalamic-pituitary-adrenal system. The test may be performed in low-dose, high-dose, eight-hour, or two-day methods

What are the Clinical Indications for performing the ACTH Stimulation Blood Test?

Following are the clinical indications for performing the ACTH Stimulation Blood Test:

  • Dehydration
  • Altered mental status
  • Nausea
  • Vomiting
  • Diarrhea
  • Fatigue
  • Salt craving

How is the Specimen Collected for the ACTH Stimulation Blood Test?

Following is the specimen collection process for ACTH Stimulation Blood Test:

Sample required: Blood

Process of obtaining blood sample in adults:

  • A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
  • The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
  • The needle cap is removed and is held in line with the vein, pulling the skin tight
  • With a small and quick thrust, the vein is penetrated using the needle
  • The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
  • The wrap band is removed, gauze is placed on the collection site, and the needle is removed
  • The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
  • The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the ACTH Stimulation Blood Test Result?

The significance of the ACTH Stimulation Blood Test result is explained:

  • An elevated ACTH Stimulation Blood Test value may indicate:
    • Cushing syndrome
    • Cushing disease
  • A decreased ACTH Stimulation Blood Test value may indicate:
    • Addison’s disease
    • Congenital adrenal hyperplasia

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • An external intake of ACTH may interfere with the results of the ACTH Stimulation Blood Test
  • The test is not helpful in differentiating between primary and secondary adrenal insufficiency

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 31, 2015
Last updated: May 26, 2018