ABSTRACT
Two systems of Competitive Enzyme linked immunosorbent assay (ELISA) were developed to detect Mycobacterial antigen in cerebrospinal fluid (CSF) for the diagnosis of tuberculous meningitis (TBM)--one by using indigenously prepared Anti-M.tuberculosis H37Rv-Penicillinase conjugate (Method I) and another by using commercially available Anti M. bovis BCG-Horse Radish Peroxidase (HRP) conjugate--(Method II). The tests were used to analyse CSF of 148 patients clinically confirmed as having TBM and 278 control subjects. By using > or = 10 ng/ml as the cut-off value for Method I and > or = 1 ng/ml as that for Method II, the specificity for both were 100% and positivity was 79.73% and 67.57% respectively. A follow up study in 26 TBM cases after 2 weeks (16 cases), 4 weeks (13 cases) and 4-12 months (10 cases) of antituberculous treatment revealed that mycobacterial antigen persisted in the majority of cases even after 4 weeks of the treatment.