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Corticotropin Releasing Factor (CRF, CRH)
Test Code92100
CPT Codes
83519<br><strong>This test is not available for New York patient testing</strong>
Preferred Specimen
3 mL plasma collected in an EDTA (lavender-top) tube
Patient Preparation
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. A morning specimen is preferred.
Minimum Volume
1 mL
Other Acceptable Specimens
Acceptable: For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.), contact the Institute for requirements and special handling.
Instructions
3 mL EDTA plasma should be collected and separated as soon as possible. Plasma should be frozen immediately after separation. Ship specimens frozen in dry ice.
Transport Temperature
Frozen
Specimen Stability
Room temperature: 1 hour
Refrigerated: 24 hours
Frozen: 6 months
Refrigerated: 24 hours
Frozen: 6 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Grossly icteric • Gross hemolysis
Methodology
Direct Radioimmunoassay
FDA Status
This test was developed and its performance characteristics determined by Inter Science Institute. Values obtained with different methods, laboratories, or kits cannot be used interchangeably with the results on this report. The results cannot be interpreted as absolute evidence of the presence or absence of malignant disease.
Setup Schedule
Set up: Varies; Report Available: 11 business days
Reference Range
<10.0 pg/mL
Clinical Significance
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.
Performing Laboratory
Inter Science Institute
944 W Hyde Park Blvd
Inglewood, CA 90302