15 PERCENT OF MICROBIOLOGY REPORTS ARE WRONG - FURTHER EXPERIENCE WITH AN INTERNAL QUALITY ASSESSMENT AND AUDIT SCHEME

Infection control teams critically depend on the quality of the diagno stic microbiology laboratories with which they are associated. Interna l quality assessment (IQA) by specimen resubmission measures the consi stency of laboratory performance and can be adapted for medical audit, but few laboratories appear to include these techniques as part of th eir quality control procedures. We established an IQA scheme in our ba cteriology laboratory in May 1989, and the mean discrepancy rate for t he first two years was nearly 15%. During the next two years covered b y this report, the scheme was extended to include audit of the consist ency of medical microbiologists' comments on reports, and a standardiz ed scoring scheme was introduced. Results from the scheme are collated and analysed thrice yearly, and laboratory techniques altered and ext ra staff training planned to reduce discrepancies. Four thousand four hundred and fourteen specimens (1.4% workload) were resubmitted, and 3 25 (7.4%) gave discrepant results. During the two years, the overall d iscrepancy rate fell consistently from 9.4 to 3.2%. Fifty-three discre pancies (1.2%) were in microscopy, and 243 (5.5%) were between culture results. Substantial decreases in technical discrepancies followed tr aining initiatives in sputum bacteriology, and training in anaerobic r ecognition and improved illumination in the anaerobic cabinet. Problem s of consistent recognition of staphylococci and of urine isolates in mixed culture, and of faecal microscopy have proved difficult to eradi cate. There was a 20.3% discrepancy rate between medical comments, but only 0.4% would have been likely to result in different patient outco mes. The cost of running the scheme was pound 4474 per annum, equating to a surcharge of pound 0.058 to each of our routine diagnostic speci mens. Discrepancies were therefore reduced by about two-thirds at a co st of pound 1.88 per discrepancy prevented; we believe this offers goo d value for money.