An algorithmic approach to thyroid function testing in a managed care setting. 3-year experience.

An algorithm (directed thyrotropin [TSH], directed thyroid testing algorithm [DRTSH]) for the initial evaluation and monitoring of thyroid function was established in our institution in 1990. The algorithm begins with measurement of TSH by a sensitive immunoassay. If TSH is either < 0.4 mU/L or > 5.5 mU/L, a free thyroid index (T4 x Resin Uptake Ratio (RU)) is automatically performed on the same sample on the same day. In the setting of a large, predominately outpatient, prepaid health care population, the algorithm reduces unnecessary testing and focuses resources on the patients who need it. Three years after its introduction, physician acceptance of this approach is high ( > 90%), test utilization is reduced, test turnaround time is reduced, and significant cost-savings can be demonstrated.