CRH Stimulation Test
The CRH stimulation test can help a doctor determine what is causing a drop or rise in a patient's adrenal hormones. CRH (corticotropin-releasing hormone) is a naturally-occurring hormone which causes the pituitary gland to secrete the hormone ACTH. ACTH tells the outer part of the adrenal gland to produce hormones such as cortisol.
A CRH stimulation test measures levels of cortisol in your blood before and after you are given a synthetic form of CRH.
The test is often used when a doctor suspects a patient has too few or too many adrenal hormones, caused by a disorder such as Cushing's syndrome. The way a patient's cortisol levels respond to the test can tell a doctor if the problem is with the pituitary glands, the hypothalamus, or the adrenal glands.
A laboratory nurse or technician will first insert a needle into a vein in one of your arms, to collect a sample of your blood. You may feel a slight sting or moderate pain when the needle is inserted to draw your blood.
The nurse or assistant will then use a needle or IV to inject the synthetic CRH into your bloodstream. Some patients feel a sensation of warmth for a short time after the CRH has been injected.
Blood samples will be taken at intervals after the CRH has been given, often 30, 60, 90, and 120 minutes after the injection. A laboratory will compare these samples with the original blood sample to help a doctor determine the cause of the hormone disorder.
The test may last from one to three hours.
You may return home after the test and resume your normal activities. Some people may feel throbbing in their arm after the test, or feel slightly dizzy or faint.
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