Concordance between milk ring test and indirect ELISA in the diagnosis of bovine brucellosis

Abstract

Concordance analysis are used to compare diagnostic methods when applied to the same group of individuals (paired samples). This article analyses the case of two laboratory methods, whose results are expressed in form of dichotomous qualitative variable (positive/ negative). In order to analyze the problem of concordance, the dual-vision method for analysis of agreement was used, which is based on a main assumption: two diagnostic methods agree when they have the same sensibility and specificity. The study analyzed 153 milk samples corresponding to the same number of herds in the central area of Chile these were classified into three strata, defined by the number of lactating cows at the time of obtaining the sample. Standard methodology of milk ring test (MRT) and indirect ELISA (ELISA-i) were performed. To determine the concordance between these two diagnostic methods, values observed in all three strata (A, B, and C) were used for each one, concordance rate (l) was calculated. Concordance rates were high in all strata, so the study concludes that both MRT and ELISA-i could be used to diagnose bovine brucellosis.