Investigation of compatibility between serological tests used in laboratory diagnosis of brucellosis

Abstract

Aim: In the diagnosis of brucellosis, the production of microorganisms in blood or bone marrow culture is considered the gold standard. But it is not always possible to produce the microorganism. For this reason, serological tests are used to diagnose brucellosis. Rose Bengal test (RB), Standard Tube Agglutination test (STA), Coombs Test (CT) and 2-Mercaptoethanol (2-ME) tests are common methods. Immunocapture-agglutination test (ICA) and Brucella Coombs Gel test (BCGT) are tests that can detect blocking antibodies along with total antibodies. The aim of our study was to determine whether there is compatibility between the tests used in diagnosis and the ICA and BCGT tests. Material and Methods: Serum samples were taken from patients with a preliminary diagnosis of brucellosis. RBT testing was performed primarily on all samples. Forty RBT positive and 40 RBT negative sera were included in the study. All serum samples were studied by STA, CT, 2-ME, ICA and BCGT methods. The compatibility between the tests were determined by using the kappa (κ) coefficient with the Cohen kappa analysis method. Results: 28 of 40 patients with RBT positive were detected as positive with STA and 2-ME and 30 of them were positive with CT. BCGT and ICA test results were found positive in all RBT positive samples. All tests results were found to be negative in 40 RBT negative samples. Cohen Kappa analysis found that compliance between RBT and BCGT and ICA (Kappa 1.0 <0.001) was excellent. Compliance between STA, BCGT and ICA tests was found to be good (Kappa 0.7 p< 0.001). CT testing showed a very good level of compatibility between ICA and BCGT (Kappa 0.8 p<0.001). There is a very good compatibility between the 2ME test, ICA and BCGT tests (kappa 0.7 0.001), Compliance between BCGT and ICA was also found to be very good (Kappa 1.0, p<0.001). Conclusion: According to these results, with the use of ICA and BCGT tests, both the number of tests will be reduced and the time to receive results will be reduced. But further studies are needed to determine the sensitivity and specificity of these tests based on culture results. But after that, we believe it can be used as a diagnostic test