Limitations of quality control in physicians' offices and other decentralized testing situations: the challenge to develop new methods of test validation.

Traditional quality-control methods are effective for detecting systematic error caused by deterioration of reagents or instruments, but ineffective for detecting sporadic error, which is more likely to occur in low-volume testing environments. Decentralized testing performed by individuals without formal laboratory training has a high potential for sporadic errors. New methods for validating test results, used each time a test result is produced, should replace current quality-control procedures. Under the rules of CLIA '88, manufacturers and the US Food and Drug Administration have an opportunity to develop new approaches to test validation.