[Comparison of the results from commercially available Brucella ELISA test kits for the investigation of bovine sera].

Bovine sera from a farm with bacteriologically confirmed brucellosis were taken for comparative serological studies using conventional methods (slow agglutination test--SAT, complement fixation test--CFT, Rose-Bengal-plate-agglutination-test--RBPT) and 5 different commercially available brucellosis ELISA testkits. These serum samples together with other infectious sera producing low level positive antibody titers in conventional tests did not react uniformly when tested by five different commercial ELISA testkits. The introduction of a standard control serum with a general cut-off resulted in a greater uniformity of ELISA results from 4 of 5 ELISA testkits and a closer approach to results of the CFT which is regarded as the confirmatory test for brucellosis. This control serum, on the other hand, was not suitable for the identification of the sensitivity of the various ELISA test kits. For this purpose, in SAT and CFT weakly positive reacting brucella sera from infected farms is needed.