The evaluation of serological tests for diagnosis of brucellosis

The aim of this study was to compare the serological tests (Rose Bengal [RB], the standard agglutination test [SAT], the enzyme immuno assay [EIA] for IgM, IgA, IgG), 2-mercaptoethanol [2-ME]) which are used routinely for the patients who had pre-diagnosis in different clinical forms of brusellosis (acute, subacute, chronic) and apply IgG avidity test and evaluate its results. Ninety two patients with SAT titers ? 1/160 enrolled and applied all tests mentioned before. IgG avidity test was performed for 78 patients in whom EIA-IgG was positive. RB test was positive for 88 (95,7 %) patients. It was found a statistically significant association between EIA-IgM and acute brusellosis. The reduction in titre in the 2-ME compared with SAT was found for 55 (59.8%) patients and the agreement with IgM was calculated as 84.8%. It was not found a statistically difference between 40% avidity index (AI) used in IgG avidity test and avidity maturation period (6 months), however, when AI was taken as 50%, İt was obtained a value (P=0.035) which was close to statistically significance threshold. It was concluded that RB and SAT tests are suitable and reliable in the serological diagnosis of brusellosis and, IgM can be an indicator of acute brusellosis and, 2-ME can be used as EIA in diagnosing IgG and IgG avidity test needs to be standardized.