Assessment of some serological tests for the diagnosis of Acute human Brucellosis

Abstract

Brucellosis is a public health problem in many developing countries including Iraq. The most reliable diagnosis of an infectious disease is confirmed by isolation of its pathogen by culture ,but It is well known that culture for Brucella is relatively difficult, time consuming and very hazardous for laboratory workers therefore it is reasonable to use serological tests for routine diagnosis of this important disease in human patients . In order to choose and evaluate the most applicable test in term of speed of performance, and accuracy , three serological tests were assayed: Rose Bengal plate test (RBPT) , Modified Rose Bengal with 2ME ,and Standard tube agglutination test (STAT) for Brucellosis. The fourth test assayed was anti brucella- IgM by Enzyme-linked immunossorbant assay (ELISA) which was used as a referent test to compare the results of the above tests with it for its high specificity and sensitivity. Blood samples were obtained from 210 patients who were highly suspected of having Brucellosis . The above 4 serological tests were performed on all serum samples . Out of the total samples , 118(56.2%) gave positive results by Roes Bengal plate test (RBPT), 58(27.6%) by 2ME , 130 (61.9%) by STAT ,and 70(33.3%) by Elisa. All negative cases by RBPT gave negative results by 2ME. Twelve samples of negative results by RBPT and 2ME were found to be positive by STAT . The sensitivity of RBPT ,2ME ,and STAT were found to be 100%,82%,and 100% respectively ,while the specificity of these three serological tests were found to be 74%,82%,and 97% respectively as compared with the results of anti Brucella –IgM by ELISA .