Thyrotropin Releasing Hormone(TRH/TRF) (Plasma)

Message

SPECIAL CONTAINER: TRH PRESERVATIVE TUBE (CALL PROCESSING)

BRING TO PROCESSING ASAP.

SPECIAL TUBE DOES NOT CLOT. SPIN AND SEPARATE PLASMA ASAP. FREEZE SPECIMEN AFTER SEPARATION.

Test Code

11830

Alias/See Also

LAB42
TRH

CPT Codes
<strong>This test is not available for New York patient testing.</strong>

Preferred Specimen

Collect 10mL blood in the special TRH preservative tube filling tube completely and separate as soon as possible. Freeze specimen immediately after separation. Special TRH preservative tubes are available from Inter Science.

Important precaution: Thyrotropin Releasing Hormone must be collected with the TRH Preservative. No other specimen is acceptable.

Patient Preparation
Patient should not be on any thyroid medication, if possible, for at least 48 hours prior to collection of specimen.

Minimum Volume

1 mL

Transport Container

Transport tube

Transport Temperature

Frozen

Methodology
Direct Radioimmunoassay

FDA Status
This test is not available for New York patient testing.

Reference Range

Baseline Level

Up to 40 pg/ml

Levels in Thyroid Dysfunction

Primary Hypothyroidism	40 - 400 pg/ml
Pituitary Hypothyroidism	100 - 600 pg/ml

Clinical Significance

Thyrotropin Releasing Hormone (TRH) is a tripeptide produced primarily by the hypothalamus. TRH is produced from a prohormone which contains multiple copies of the TRH molecule meaning that several TRH entities can be released from one precursor. It has a stimulatory effect on the pituitary releasing Thyrotropin (TSH). TRH secretion is controlled in a negative feedback system by thyroid hormones. Binding of TRH to its receptor causes a rise in calcium which initiates TSH secretion. It also stimulates adenyl cyclase in the pituitary. TRH also stimulates secretion of Prolactin, Growth Hormone in Acromegaly, and ACTH in Cushing's and Nelson's Syndromes. Levels of TRH are non-detectable or very low in patients with Hyperthyroidism and Hypothalamic Hypothyroidism. Levels are elevated in patients with Primary and Pituitary Hypothyroidism.

Performing Laboratory

Interscience Institute

944 W Hyde Park Blvd

Inglewood, CA 90302-3308

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.