Code Details for Lab and Clinical Services
ISI Order Code:
TRH
CPT Code:
83519
Clinical Significance of Thyrotropin-Releasing Hormone (TRH)
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 Hypothyroidis
Reference Range, Procedure & Expected Results
Reference Range:
Up to 40 pg/ml
Procedure:
Thyrotropin Releasing Hormone is measured by direct radioimmunoassay.
Expected Turnaround Time:
10 Business Days
Turnaround time is defined as the usual number of days from the date of receipt of a specimen for testing to when the result is released to the ordering facility.Report: Sample Report
Pre-Test Preparation Guidelines
Patient should not be on any thyroid medication, if possible, for at least 48 hours prior to collection of specimen.
Specimen Collection Instructions
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.
Minimum specimen size is 1 ml.
Please contact ISI for separation using a non refrigerated centrifuge. Contact ISI for details.
The Inter Science Institute TRH Preservative collection and preservative tube is intended for use with Inter Science Institute’s Thyrotropin Releasing Hormone (TRH) assay only. It has not been validated for use with other in vitro assays. Effects of using this device other than as intended are unknown, and is not recommended.
TRH Important Precautions
Thyrotropin Releasing Hormone must be collected with the TRH Preservative. No other specimen is acceptable.
TRH Assay Rejection Criteria
Gross hemolysis/lipemia/icteric
Shipping and Handling Instructions for TRH Assay Specimens
Special Specimens:
For tumor/tissue and various fluids (i.e. CSF, peritoneal, synovial, etc.) contact the Institute for requirements and special handling.
Shipping Instructions:
Ship specimens frozen in dry ice.
Research & Scientific References
- 1. MM Kaplan, JA Taft, S Reichlin, and TL Munsat. Sustained Rises in Serum Thyrotropin, Thyroxine, and Triiodothyronine during Long Term, Continuous Thyroid Releasing Hormone Treatment in Patients with Amylotrophic Lateral Sclerosis. Journal of Clinical Endocrinology and Metabolsim 63: 808, 1986.
- 2. GE Shambaugh III, JF Wilber, E Montoya, H Ruder, and ER Blonsky. Thyrotropin-Releasing Hormone (TRH): Measurement in Human Spinal Fluid. Journal of Clinical Endocrinology and Metabolism 41: 131, 1975.