The agreement rate of rose Bengal, modified rose Bengal and rapid Wright tests for detection of positive serum sample of Brucellosis

Background: Rose Bengal is a common test for serologic diagnosis of brucellosis. The aim of this study was to evaluate the agreement rate between modified rose Bengal, rose Bengal and rapid Wright tests for detection of antibody positive serum samples. Methods: Cross section study was designed. 941 serum sample of patients referred to the central medical laboratory of Kermanshah, were evaluated by rose Bengal, modified rose Bengal and rapid Wright, using convenient sampling method. Positive samples were confirmed and their titers were defined by Wright agglutination test. Results: The number of positive serum samples with modified rose Bengal was two fold higher than conventional rose Bengal test (P<0.001), which included all positive samples with rose Bengal. On the other hand, although the number of positive diagnosed serum samples with modified rose Bengal were nearly two times more than Wright test (P<0.001), but it did not include all positive samples detected by Wright test. All three tests showed acceptable agreement rate (k≥0.583).Conclusion: Results of this study confirmed that modified rose Bengal able to detect more positive serum sample than conventional rose Bengal and it would be substituted rose Bengal. However, the rapid Wright test should be used aside with modified rose Bengal, because it could not cover all positive samples detected by rapid Wright test.