Multi-antigen and antibody assays (SEVA TB ELISA) for the diagnosis of tuberculous pleural effusion.

OBJECTIVE: Prospective evaluation of inhouse developed SEVA TB ELISA using cocktail of Mycobacterial antigens ES-31 and EST-6 (containing ES-38 and ES-41) and their specific antibodies in the diagnosis of Tuberculous pleural effusion was done in a tertiary care hospital.
METHODS: Detection of circulating free and immune-complexed (IC) antigens and antibody by sandwich and indirect peroxidase ELISA respectively was done in pleural fluid and sera specimens. Total 33 patients with pleural effusion, including 24 patients diagnosed as tuberculous pleural effusion based on clinico-radiological, microbiological and biochemical profile (protein, LDH and ADA) of pleural effusion and nine patients with non-tuberculous pleural effusion, were studied.
RESULTS: Pleural fluid showing either antigen or immune-complexed antigen or antibody positive was considered as ELISA positive for tuberculous pleural effusion. Multi antigen and antibody assay (SEVATB ELISA) showed 100% specificity and 83% sensitivity in pleural fluid while 78% specificity and 92% sensitivity in serum of tuberculous pleuritis patients.
CONCLUSION: This study showed usefulness of SEVATB ELISA, using cocktail of ES-31 and EST-6 antigens and their antibodies for antibody and antigen detection respectively in analysis of either sera or pleural fluid samples of suspected tuberculous pleuritis patients as an adjunct test to clinical diagnosis.