The importance of an effective proficiency testing program to the regulation of clinical laboratories. The view from one state.

The increased utilization of private proficiency testing services by regulators to evaluate the performance of clinical laboratories is discussed. The author outlines some of the changes that have occurred in the field of laboratory medicine that appear to indicate that proficiency testing is the single most cost-effective means for regulators to evaluate laboratories. Therefore, the need to continue to improve the proficiency testing process is stressed.