Antibiotic susceptibility testing accuracy. Review of the College of American Pathologists Microbiology Survey, 1972-1983.

The antibiotic susceptibility testing results for the College of American Pathologists' Microbiology Surveys subscribers for 1981 to 1983 were compared for accuracy and problem areas with earlier data dating back to 1972. Disk diffusion (Kirby-Bauer) test accuracy was 96.3%, 96.4%, and 95.0% for the Bacteriology, Comprehensive, and Basic Surveys participants, respectively. The overall dilution test and automated system (Autobac I) accuracy was 95.8% and 93.8%, respectively. More laboratories (more than 40% of bacteriology and comprehensive laboratories) were using dilution minimum inhibitory concentration tests, usually frozen-form commercial systems. The current test accuracy was comparable with data for previous years, but the Basic Survey subscribers have demonstrated improvement since mid-1981. Several testing problems were identified, principally in the interpretive criteria available in national consensus publications such as the National Committee for Clinical Laboratory Standards M2-A3. Many of these problems have recently been resolved through the cooperation of the National Committee for Clinical Laboratory Standards' subcommittees and the College of American Pathologists' surveys.