
Thyrotropin Releasing Hormone (TRH) also called Thyrotropin Releasing Factor (TRF), thyroliberin or protilerin. Its function is to control the release of
thyroid stimulating hormone (TSH) which produces thyroid hormones responsible for the growth of thyroid gland by the anterior pituitary.
Thyrotropin Releasing Hormone Stimulation Test
It is use to monitor patients who have hyperthyroidism or hypothyroidism. it is use to detect residual TSH stores in the
pituitary gland. It is the confirmatory test for primary hyperthyroidism. it is also use to detect thyroid hormone resistance syndromes. it can differentiate secondary hypothyroidism from tertiary hypothyroidism. WheN a TRH is injected on a patient with secondary hypothyroidism, the TSH level will not increase but when TRH is injected with patient that suffers with tertiary hypothyroidism it will respond to TRH stimulation.
Specimen:
Red Tap or EDTA
Intravenous 200 – 500 ug of synthetic TRH
specimen free from lipemia and hemolysis
Procedure:
>The test is performed in the morning, with a overnight fasting.
>Samples for TSH are drawn before 30 minutes and 60 minutes before the administration of TRH.
>TRH is injected intravenously.
Side Effects And Risks:
It may cause nausea, vomiting and urge to urinate. It may also cause constriction of the blood vessel which can lead to hemorrhage in patients with pre existing pituitary tumors.
Reference:
http://www.clinlabnavigator.com/Tests/ThyrotropinRelHormoneStimTest.htmlhttp://en.wikipedia.org/wiki/Thyrotropin-releasing_hormoneClinical Chemistry Principles, Procedures, Correlations
by: Michael L. Bishop, Janet L. Duben-Engelkirk and Edward P. Fody