Thyrotropin-releasing hormone tests in an outpatient clinic

Measurement of thyroid-stimulating hormone (TSH) levels in various timed blood samples after administration of thyrotropin-releasing hormone (TRH) has become a standard part of the diagnostic armamentarium for suspected thyroid disease. We reviewed the records of 165 patients who received TRH tests in an endocrinology outpatient clinic to assess the diagnostic utility of the test based upon other clinical parameters, and to assess concordance of the 30-minute TSH value after intravenous administration of TRH. Standard (control) values for TRH testing were obtained in 41 normal subjects. Patients were divided into groups of hyperresponders, hyporesponders, and normal responders. The overall concordance rate of the ultimate thyroid diagnosis and the 30-minute TSH value was 97%. With close adherence to clinical indications, the TRH test is of considerable benefit as an outpatient tool in the diagnostic assessment of thyroid disease. Basal and 30-minute TSH values are satisfactory for diagnosis in the majority of patients, thereby rendering unnecessary the discomfort and expense of multiple samples for TSH measurements.