DEVELOPMENT OF AN INTERNAL QUALITY ASSESSMENT SCHEME IN A CLINICAL BACTERIOLOGY LABORATORY

Aim-To develop an internal quality assessment (IQA) scheme in a clinic al bacteriology laboratory. Methods-Over 24 months, 1230 diagnostic sp ecimens, representing 0.42% of laboratory workload, were anonymised an d resubmitted for analysis. Six hundred and twenty one (48.7%) of thes e gave positive culture results; 44 fecal and upper respiratory specim ens were ''spiked'' (artificially inoculated) to increase the proporti on of positive samples. Results-Discrepancies between IQA and clinical sample results occurred in 188 cases (14.8%): 76.6% of these were in culture results, 13.3% in microscopy performance, and 10.1% in clerica l recording. The culture discrepancy rate for each positive sample was lowest for wound (17.5%) and urine (18.1%) specimens, and highest for faeces (34.9%) and upper respiratory (37.7%) samples. Discrepancies i n several areas responded to staff training and improvement in technic al methods. Conclusions-An IQA programme of this type assesses the rep roducibility of tests within a diagnostic laboratory when analysing co mmon specimen types and organisms. It permits blind assessment of many areas of diagnostic work that are not readily amenable to other quali ty assurance methods, and it raises the awareness of all staff to the importance of quality in every aspect of specimen and data processing.