Inaccuracy of house staff in reading throat cultures

The low prevalence of streptococcal pharyngitis in our pediatric clinic during a normally high-prevalence period encouraged us to examine the accuracy of throat culture readings made by the house staff. Six pediatric residents processed 256 cultures, which were then reinterpreted by a microbiologist. The residents consistently underread the cultures, failing to identify 68 (60%) of 112 with beta-hemolysis and 23 (58%) of 40 with a zone of bacitracin inhibition. This inaccuracy in interpretation of throat cultures emphasizes the physician's need to periodically reassess these skills.