Comparison of the Methods Used in the Diagnosis of Brucellosis

Abstract

Objective: The aim of the present study was to compare the new serological tests “immuncapture agglutination” (Bru- cellacapt, Vircell, Granada, Spain), enzyme-linked immunosorbent assay (ELISA) and the classical tests for diagnosis of acute, subacute or chronic brucellosis. Methods: Forty-nine samples of patients who presented with fever and clinical suspicion of brucellosis and who were admitted to Infectious Disease Department of Erciyes University Hospital with agglutination (SAT) titers ≥1/10 were collected during 2010 and 2012. And 30 healthy volunteers were enrolled in the study. All samples were subjected to the Brucella spp. Spesific culture, STA test, Brucellacapt test and ELISA for detection of IgM, IgA, and IgG. Coombs test was performed for 28 samples with titers <1/160 as measured by STA. Cohen’s kappa test was used to evaluate the correlation between the tests. Results: Blood culture was positive in 6 (12, 2%), joint fluid culture in 2 (4%), STA test in 21 (42, 8%), Brucellacapt test in 36 (73.4%), ELISA IgG in 33 (67.3%), ELISA IgM in 33 (67.3%), ELISA IgA in 31 (61.2%) of 49 patients. While STA, brucellacapt ve ELISA IgA tests were negative in all of the control group (n=30), in four individuals (%13.3) ELISA IgG, three individuals (%10) ELISA IgM were found low positive. When STA test was taken as the reference method, the sensitivities were found to be 100% in brucellacapt test, 85.7%, 90.4%, 90.% in ELISA IgG, IgM, IgA respectively and 23.8% in blood culture. Specifities were 74.1%, 67.2%, 67.2%, 79.3% and 98.2% respectively. When presence of clinical findings are taken as a reference, brucellacapt test was found to be most compatible (κ=0,66). Conclusions: STA was found to be unsatisfactory in the diagnosis of brucellosis in patients. Brucellacapt and/or ELISA tests are suggested to be used to verify results of STA.