ABSTRACT
Serum samples from 200 vaccinated adult bovine females from two herds were analyzed by buffered antigen acidified plate test (AAT) (Rose Bengal Plate Test), indirect enzyme-linked immunosorbent assay (ELISAI), 2-mercaptoethanol test (2-ME) and complement fixation test (FC). For ELISAI, the fixed value of 45 percent positivity (PP) was used. Group A was composed of 100 animals, with description of reproductive disturbances compatible with brucellosis and reagent to the AAT. Group B was composed of 100 animals serologically free of B. abortus for at least two years. Additionally, all serum samples were tested using the AAT, the 2-ME and the FC to confirm negative status. The combination of two tests, FC and 2ME was used as the gold standard. The relative sensitivity and specificity and the Kappa were calculated for each test. The result of kappa for 2-ME in relation to the FC and of the AAT and the ELISAI in relation to the gold standard was, respectively, 0.78, 0.86 And 0.84. The relative sensitivities (Sr) were, respectively, 84.1% (53/63), 100% (53/53) and 98.1% (52/53), and the relative specificities (Er) were 93.3% (111/119), 90.1% (100/111) and 90.1% (100/111). For comparison between the ELISAI and the AAT, there was obtained a Kappa of 0.91, Sr of 93% (93/100) and Er of 98% (98/100). Conclusions: 1 The option of constituting the gold standard based on at least two tests was the most suitable for this study; 2 The ELISAI resulted in values of Sr and Er similar to the AAT. Therefore, the AAT and the ELISAI are good for screening in regard to the diagnosis of brucellosis.