Prospective study of SEVA TB peroxidase assay for cocktail antigen and antibody in the diagnosis of Tuberculosis in suspected patients attending a tertiary care hospital located in rural area

ObjectiveTo evaluate inhouse developed SEVA TB peroxidase enzyme immunoassay using cocktail of mycobacterial excretory-secretory antigens (ES-31, ES-43 & EST-6) for antibody detection and their affinity purified antibodies for antigen detection in tuberculosis suspected patients.MethodsInhouse developed SEVA TB peroxidase enzyme immunoassay was evaluated prospectively in 73 suspected pulmonary and 46 extra-pulmonary tuberculosis patients during November 2008∼March 2009 in a tertiary hospital located in rural area.ResultsAssay on prospective analysis showed 100% correlation of pulmonary tuberculosis (PTB) and extra-pulmonary tuberculosis (EPTB) acid fast bacilli positivity and antitubercular treatment in 11 cases. Thirty nine PTB and 12 EPTB cases showed negative for ELISA test and were also not given antitubercular therapy. However 30 PTB and 27 EPTB cases showing ELISA positivity were neither acid fast bacilli positive nor antitubercular therapy treated. These cases may possibly have dormant infection and need further diagnosis. In EPTB cases ELISA was observed to be more useful than AFB smear test.ConclusionsThis inhouse developed user-friendly peroxidase ELISA can be used as an adjunct test of smear microscopy or culture techniques for routine screening of patients suspected of PTB or EPTB.