Diversity of Urine Bacteriology Practice in Ontario: An External Quality Assessment

Abstract

OBJECTIVE: Assessment of urine bacteriology practice in Ontario regarding appropriateness of quantification and the accuracy and Système International d’Unités (SI) conformity in the reporting of results.DESIGN AND SETTING: A simulated urine specimen with Escherichia coli at a target of 100×10 colony forming units (CFU)/L was submitted to licensed Ontario bacteriology laboratories. Data on the isolation and quantification of the pathogen were required within a stipulated time. Reference values were determined by consensus agreement of the findings of seven designated laboratories.PARTICIPANTS: The challenge was administered to 182 Ontario laboratories licensed to perform urine bacteriological assessment. There was no stratification by type or complexity of facility.MAIN OUTCOMES: Samples were processed by routine procedures. Date and time of receipt of the sample, date tested, bacterial count, associated quantification units and the method used were the data required. A copy of the report using the laboratory’s normal reporting format to user-physicians was requested.RESULTS: The organism was isolated and correctly identified by 179 laboratories. Only 58% of laboratories reported a count of 100×10³ CFU/L or more, with 42% reporting a count of between 10 and 100×10³ CFU/L. The majority used a standard 0.001 mL loop method. Only 87 participants reported using the correct notation of SI units, although a further 65 reported as CFU/L.CONCLUSION: The variety of reporting formats is of concern. Processing and reporting should be standardized. Laboratories should provide an explanatory note or interpretation when nomenclature or format of a report is changed.