A regional quality control program in microbiology. II. Advantages of simulated clinical specimens.

A regional quality control program was established using simulated clinical specimens introduced into the routine workload of participating laboratories in such a way that they were not detected as quality control specimens. Comparison of performance between these specimens and lyophilized cultures showed that additional information was obtainable with the former. In particular, it was observed that common pathogens such as Escherichia coli are poorly identified in clinical material. The examination of urines was inferior to examination of other types of specimens. The implications of these findings for the practice of diagnostic bacteriology are discussed.