Analytic Time
 
Soft Order Code
MMLR

Test Updated:

Synonyms

Corticotropin Releasing Hormone (CRH)

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Test Overview

Test Methodology

Direct Radioimmunoassay

Test Usage

Corticotropin Releasing Factor is a 41 amino acid peptide produced in the hypothalamus. It stimulates the release of ACTH from the pituitary which in turn releases Cortisol from the adrenal gland. The Cortisol produced rapidly shuts off CRF secretion acting as a negative feedback control. CRF also releases b-Endorphin, b-Lipotropin and other related proopiomelanocortin peptides. Ectopic tumors producing ACTH also frequently produce CRF. In these patients ACTH usually does not respond to Dexamethasone suppression. CRF is markedly elevated in third trimester pregnancy. Most of it is produced by the placenta and is bound to CRF-Binding Protein and is biologically inactive. The CRF stimulation test is the most effective method of differentiating primary from secondary adrenal insufficiency and in differentiating hypothalamic from pituitary causes.

Reference Range

Up to 10 pg/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection

Patient should be fasting 10 - 12 hours and should not be on any corticosteroid, ACTH, or estrogen medications, if possible, for at least 48 hours prior to collection of specimen. An am specimen is preferred. Collect specimen in a lavender top tube, aliquot plasma into a plastic vial and freeze immediately.

Lavender Top Tube
Normal Volume
3 mL EDTA plasma
Minimum Volume
1 mL EDTA plasma

Billing Information

CPT Code
82528
Pro Fee Code
 
LOINC
 

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.