Interlaboratory proficiency testing as a tool for improving performance in laboratories diagnosing bovine mastitis

The National Veterinary and Food Research Institute (Finland) and the Veterinary Laboratories Agency of the Quality Assurance Unit, Department for Environment, Food and Rural Affairs, United Kingdom (previously the Ministry of Agriculture, Fisheries and Food) organized a proficiency testing program for laboratories analyzing veterinary mastitis samples. Three test samples with lyophilized strains of common aerobic bacteria were sent to the participating laboratories 7 times between 2000 and 2003. The participants returned 98% of the requested data. The overall performance of the laboratories varied from 63 to 93% in different testing rounds. All laboratories diagnosed Staphylococcus aureus and Escherichia coli correctly at every round. Improvement in diagnosing individual bacteria was observed for Staphylococcus epidermidis, Streptococcus dysgalactiae, Enterococcus spp. and Klebsiella spp. The overall performance of the laboratories improved with increased participation. The educational role of the program was important. Laboratories working in the veterinary field should implement a documented quality system covering all functions of the laboratory, as well as a planned quality assurance system.