Corticotropin Releasing Factor (Plasma)

Test Code

92100

CPT Codes
83519

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

Instructions

3 mL EDTA plasma should be collected and separated as soon as possible.
Plasma should be frozen immediately after separation.

Special specimens: For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.), contact the Institute for requirements and special handling. Ship specimens frozen in dry ice.

Transport Container

Transport tube

Transport Temperature

Frozen

Specimen Stability

Room temperature: 1 hour
Refrigerated: 24 hours
Frozen: 6 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Serum will be rejected. This is a plasma only test.

Methodology
Direct Radioimmunoassay

FDA Status
This test was developed and its performance characteristics determined by Inter Science Institute. It has not been cleared or approved by the US Food and Drug Administration. The FDA has determined that such clearance is not necessary.

Setup Schedule

Set up: As received; Report Available: 15 days

Reference Range

See Laboratory Report

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

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.