Use of an indirect elisa for Brucella abortus diagnosis in Cuba

Introducing immunoassays in Brucella diagnosis requires a comparative study with reference techniques such as the complement fixation reaction (CFR). Sensitivity and relative specificity studies allowed us to observe the behaviour of this immunoassay, using samples from free of disease, free by vaccination and affected areas. Sensitivity results for a cut-off point of 40PP and a confidence interval of 95% ranged from 94.8 to 99.5% and the specificity between 94.1 and 97.5%. For free of disease areas a cut-off point of 22 PP was calculated that reached a 99% specificity. This immunoassay for the detection of antibodies against Brucella abortus must be used with two different cut-off points, depending on the epidemiologic conditions of the country, with CFR in affected or vaccinated areas as a confirmative method. (author)