CPT® Code 80438

Thyrotropin releasing hormone (TRH) stimulation panel; 1 hour This panel must include the following: Thyroid stimulating hormone (TSH) (84443 x 3)

The Thyrotropin releasing hormone (TRH) stimulation panel, identified by CPT® Code 80438, is a diagnostic test used to evaluate the function of the pituitary gland and the hypothalamus in relation to thyroid hormone regulation. This panel specifically assesses the response of thyroid stimulating hormone (TSH) levels following the administration of TRH, which is a hormone released by the hypothalamus when there are low levels of thyroid hormones (T4 and T3) in circulation. The TRH stimulates the pituitary gland to release TSH, which subsequently prompts the thyroid gland to produce and release T4 and T3 hormones. The test is particularly useful in diagnosing conditions such as pituitary and tertiary hypothyroidism. However, it is important to note that the TRH stimulation test has largely been supplanted by the third-generation TSH test due to the limited availability of the drug Protirelin, which is necessary for the test. The procedure involves the insertion of an intravenous line, from which baseline blood samples are drawn to measure TSH levels. Following this, Protirelin is administered via IV push, and additional blood samples are collected at specified intervals to monitor the TSH response. The serum or plasma samples are then analyzed using a quantitative chemiluminescent immunoassay to determine the TSH levels accurately.