Yale New Haven Hospital

Department of Laboratory Medicine
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Thyrotropin releasing hormone

Lab Section: 

Sendout Reference


Lab Location: 


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Test ID: 




Radioimmunoassay (RIA)




20 days

Specimen Requirements: 

Collection: 3.0 mL Blood in a Call Lab.
Pediatric volume: 1 mL.
5 mL EDTA specimen should be collected in the special TRH preservative tube and separated as soon as possible. Freeze specimen immediately after separation. Minimum specimen size is 1 mL. Must call Chemistry Reference to obtain special TRH-preserved tube
Transport: Frozen.
Handling: Ship specimens frozen on dry ice. This test is not valid unless it has been collected with the TRH Preservative available from ISI.
Stability: Room temperature: Unacceptable Refrigerated: Unacceptable Frozen: 6 months



Clinical Indications: 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 nondetectable or very low in patients with hyperthyroidism and hypothalamic hypothyroidism. Levels are elevated in patients with primary and pituitary hypothyroidism.

Thyrotropin Releasing Hormone must be collected with the TRH Preservative. No other specimen is acceptable. Performing laboratory: Inter Science Institute 944 W Hyde Park Blvd Inglewood, CA 90302

Reference Interval: 

See patient report or consult reference laboratory website.


CPT Code(s): 


Last Changed: 

8/16/2017 5:48:20

Last Reviewed: 

8/16/2017 5:48:20