TRH stimulation test

The thyrotropin releasing hormone stimulation test was the standard way of confirming hyperthyroidism prior to the development of immunoassay tests. It was performed by taking a base level of thyrotropin stimulating hormone, and then giving the patient a fixed dose of thyrotropin releasing hormone. The level of thyrotropin stimulating hormone would then be tested 15 minutes and 30 minutes after the dose. In a patient with hyperthyroidism, these levels could be measured with the less sensitive assays that were used.
At present, the test is still used to confirm hyperthyroidism where the suspected problem is a malfunction of the pituitary gland or the hypothalamus.
The test is rarely dangerous, but can cause nausea and the urge to urinate.
TRH stimulation test at Wikipedia