Effect of Serum Treatment with Chloroform on Increasing Specificity of Rose Bengal Test for Diagnosis of Brucellosis

Abstract

To address the effect of serum treatment with chloroform (STC) on increasing the specificity of the Rose Bengal test (RBT), 200 serum samples (n=100 buffaloes and n=100 cows) were tested. For each animal species, 50 were apparently healthy and 50 were aborted. RBT and indirect enzyme-linked immunosorbent assay (iELISA) were applied for testing the serum before and after treatment with chloroform. The coherence between tests was poor (K=0.004, SE=0,003), (K=0.031, SE=0.24) and (K=0.176, SE=0,143) for apparently healthy buffaloes, apparently healthy cows and aborted buffaloes respectively, but it was only fair (K=0.386, SE=0,185) for aborted cows. After STC, the coherence between tests was markedly improved, where it became perfect (K=1.0, SE=0.0), (K=0.834, SE=0.113) and very good (K=0.896, SE=0.071) for apparently healthy buffaloes and cows, aborted cows and aborted buffaloes. The specificity and sensitivity of RBT were obviously raised after STC recording (100% and 100%), (80% and 100%) and (75% and 100%) for apparently healthy buffaloes and cows, aborted buffaloes and aborted cows respectively. Current results recommended that STC is a reliable method to avoid false positives. The higher specificity and sensitivity obtained by RBT after using STC suggests that it is not only can be used as a rapid, simple, economical and convenient screening method but also it can be used as a confirmatory test for serodiagnosis of brucellosis for large scale in endemic areas.