Isolation and identification of Burkholderia cepacia by participants in an external Quality Assurance Program (QAP) between 1994 and 1999

External quality assurance programs (QAPs) provide an opportunity to benchmark laboratory performance according to the profile of specimens received. Participant confidentiality is maintained within each group of laboratories whose performance is measured using similar, repetitive exercises. Isolation and identification of Burkholderia cepacia from simulated cystic fibrosis (CF) sputa was a clinically relevant exercise that provided a model for this analytical approach.

Between 1994 and 1999, six Royal College of Pathologists of Australasia (RCPA) Microbiology QAPs included four simulated CF sputa and two panels of oxidative Gram-negative bacilli. Laboratories were grouped according to experience with CF sputa disclosed by two questionnaires. Data were analysed by laboratory group for ability to isolate and identify B. cepacia.

Three laboratory groups annually received >100 CF sputa (CF>100), 100 CF sputa or fewer, or did not regularly receive CF sputa. CF>100 laboratories inoculated more isolation media, were more likely to use selective media and were less likely to misidentify B. cepacia than the other groups. Improved performance by CF>100 laboratories was marked after the first exercise and remained at a high level compared with the other two groups. This trend in performance was also apparent for Pseudomonas aeruginosa although the numbers of errors were less than for B. cepacia.

These exercises demonstrated consistently improved performance only among CF>100 laboratories. The future criteria for laboratory accreditation may include performance as well as participation in QAPs, placing additional burdens on organisers and participants.