REASONS FOR PROFICIENCY TESTING FAILURES IN CLINICAL-CHEMISTRY AND BLOOD-GAS ANALYSIS - A COLLEGE-OF-AMERICAN-PATHOLOGISTS Q-PROBES STUDY IN 665 LABORATORIES

Objective.-To determine the reasons for proficiency testing (PT) failu res from 41 chemistry and blood gas analytes using data collected to b enchmark performance. Design.-Self-administered survey requesting numb er of challenges by analyte encompassing nine PT events. When the chal lenge resulted in a self-defined failure, further information was requ ested concerning the magnitude of the failure (as a standard deviation index) and categorization of the type of failure into six major group s (Methodologic, Technical, Clerical, Survey, Unexplained, or Other) a nd then into subgroups. Participants.-Laboratories enrolled in the 199 2 College of American Pathologists Q-Probes program. Main Outcome Meas ures.-Rate of PT failures and reasons for failure. Results.-Proficienc y testing data from 670 489 challenges performed in 665 laboratories r evealed 9268 (1.4%) unacceptable results. Failure types were distribut ed as follows: Methodologic, 33.5%; Technical, 17.4%; Clerical, 11.1%; Survey, 7.8%; Unexplained, 25.7%; and Other, 7.4%. Conclusions.-Indiv idual analyte PT failure is a common event in the participating labora tories, but failures in successive or alternate events are rare. Analy sis of the reasons for failed events indicates that most identified re asons occurred in either the Methodologic or Technical categories (50. 9%). Analysis of the failure types suggested investigation pathways ba sed on the magnitude of the failure that could reduce the 25.7% rate o f unexplained failures.