A proficiency testing method for detecting antibodies against Brucella abortus in quantitative and qualitative serological tests.

A proficiency testing panel for detecting antibodies against Brucella abortus was developed and evaluated by both primary binding and conventional serological tests, using the guidelines of the World Organisation for Animal Health and the International Organization for Standardization Guide 43-1. All serological tests were judged satisfactory. Among the primary binding tests, the competitive enzyme-linked immunosorbent assay (ELISA 2) and the indirect enzyme-linked immunosorbent assay (ELISA 1), with standard deviation indices (z-scores) of -0.06 and 0.10, respectively, performed best. Similarly, E(n) numbers (i.e. a way of comparing different measurements of performance) of 0 for both the competitive ELISA 2 and the indirect ELISA 1 indicated that these tests performed best in the initial round of proficiency testing. The conventional serological tests all passed the panel. Comparing data from both the quantitative and qualitative tests demonstrated that this proficiency testing scheme was fit for the purpose for which it was designed.