What are other Names for this Test? (Equivalent Terms)
- Corticoliberin Stimulation Blood Test
- Corticotropin-Releasing Factor Stimulation Blood Test
- CRF Stimulation Blood Test
What is Corticotropin-Releasing Hormone Stimulation Blood Test? (Background Information)
- Corticotropin-releasing hormone (CRH) is a hormone that is produced by the hypothalamus of the brain. It eventually causes the release of stress hormones such as cortisol and aldosterone. The hypothalamus is located in the base of the brain, near the brainstem. It produces and releases CRH among other hormones
- The CRH travels a short distance to the anterior pituitary gland, which is located directly beneath the hypothalamus. There, CRH causes the anterior pituitary gland to release adrenocorticotropic hormone (ACTH). The ACTH stimulates the adrenal glands (small, pyramid-shaped organs located above each kidney) to produce stress hormones such as adrenaline and cortisol
- Adrenaline, also called epinephrine, 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 so by stimulating the fat cells to release fatty acids into blood for immediate use
- Another effect of cortisol is to suppress inflammation, which it does 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
- After ACTH causes the adrenal gland to release its various hormones, these hormones act back on the hypothalamus and pituitary glands to prevent further release of hormones. This process is called negative feedback
- The Corticotropin-Releasing Hormone Stimulation Blood Test measures levels of CRH in blood after stimulation by a compound similar to the hormones produced by the adrenal glands; the compound is called dexamethasone
- The Corticotropin-Releasing Hormone Stimulation Blood Test assesses the negative feedback process of CRH and ACTH. It is used to determine the cause of elevated ACTH levels
- The Corticotropin-Releasing Hormone Stimulation Blood Test consists of measuring ACTH and cortisol levels, then administering CRH and measuring ACTH and cortisol levels 5, 10, 15, 30, 45, 60, 90, and 120 minutes after CRH administration
What are the Clinical Indications for performing the Corticotropin-Releasing Hormone Stimulation Blood Test?
Following are the clinical indications for performing the Corticotropin-Releasing Hormone Stimulation Blood Test:
- Altered mental status
- Salt craving
How is the Specimen Collected for Corticotropin-Releasing Hormone Stimulation Blood Test?
Following is the specimen collection process for Corticotropin-Releasing Hormone 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 Corticotropin-Releasing Hormone Stimulation Blood Test Result?
- A normal or high value for the Corticotropin-Releasing Hormone Stimulation Blood Test may indicate pituitary Cushing disease
- No response to the Corticotropin-Releasing Hormone Stimulation Blood Test may indicate ectopic ACTH secreting tumor
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:
- Certain factors may interfere with the results of the Corticotropin-Releasing Hormone Stimulation Blood Test. These include pregnancy and external intake of ACTH
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.