In-use evaluation of a commercially available set of quality control cultures

Increasing awareness of the need for a uniform quality control program prompted an evaluation of a commercially available set (Bact-Chek) of eight organisms. A protocol was designed in which this set of control cultures was tested simultaneously in the clinical microbiology laboratory of a 400-bed hospital (the Berkshire Medical Center) and in the reference laboratories of the Bacteriology Section of the Center for Disease Control. The results indicate that the Bact-Chek organisms are essentially as advertised: they constitute a basic set of cultures for a quality control program in clinical microbiology. Ninety per cent of the media and reagents (excluding mycobacterial media and reagents) in the clinical laboratory were checked with this set of eight cultures. Additional cultures not in the set were used to check the remaining 10% of the media and reagents.