A comparison of Brucella IgG and IgM ELISA assays with agglutination methodology

Despite brucellosis having a low incidence rate in developed nations, it still remains the leading zoonotic disease in the world. Culturing of Brucella spp. provides good specificity but in cases where the fever is intermittent, sensitivity is problematic. This has led to the development of serological methods of detection. Brucella agglutination methods have been considered the serological gold-standard since their inception, although commercial Brucella IgG and IgM enzyme-linked immunosorbent assays are available to potentially aid in the diagnosis of the disease. In our study, anti-Brucella IgG and IgM assays were compared with agglutination. Individually the IgG assay tested had an accuracy of 56% and the IgM assay had an accuracy of 77%. These poor accuracies reinforce Centers for Disease Control's conclusion that nonagglutination tests should not be used to confirm brucellosis.