SEVA TB ELISA – Multi antigen and antibody assays for serodiagnosis of suspected cases of pulmonary and extra pulmonary tuberculosis in tertiary care hospital –A retrospective study

Abstract

ObjectiveTo assess the usefulness of in-house developed multiantigen and antibody assays, in diagnosis of both pulmonary and extra-pulmonary tuberculosis. MethodClinically suspected cases of 31 pulmonary and 171 extra-pulmonary tuberculosis (TB) were screened by ELISA using cocktail (ES-31 + EST-6) antigen and their specific antibodies (anti ES-31 + anti EST-6 IgG) for detection of antibody and and antigen (circulating antigen and immune complexed antigen) respectively and correlated with antituberculosis therapy in retrospective study. ResultsOut of 31 cases of pulmonary TB screened, 15 patients showed ELISA positivity out of which five cases were given antituberculosis therapy. Out of 171 cases of EPTB screened, 76 cases showed ELISA positivity out of which 18 were given antituberculosis therapy. Further 4 EPTB cases which showed AFB negativity were given ATT. The data was further analyzed based on PTB & EPTB, adults and children, OPD and IPD patients to understand false positivity in clinically suspected PTB and EPTB cases. There was significant correlation (108/202 cases) with ELISA negativity and no ATT advised in clinically suspected PTB and EPTB patients. ConclusionsIn house developed multi antigen and antibody assays have been observed to be quite useful as adjunct test in serodiagnosis of suspected cases of tuberculosis in particular extrapulmonary tuberculosis.