Penicillinase ELISA for detection of tubercular antigen in tuberculosis

Stick sandwich enzyme linked immunosorbent assay (ELISA) using rabbit anti PPD-RT 23 immunoglobulins and enzyme penicillinase has been explored for detection of tubercular antigen in sera and CSF samples of pulmonary tuberculosis and tubercular meningitis (TBM) respectively. The analysis of sera showed 73.3% of pulmonary tuberculosis cases, 16.2% of healthy controls and 44.4% of Hansen's disease positive for tubercular antigen. The accuracies of positive and negative predictive values were 69% and 82% respectively. The analysis of CSF samples showed the presence of tubercular antigen in 76.4% of TBM, 16.6% of pyogenic meningitis cases, 19.4% of neurological diseases other than meningitis and 16.1% non-neurological disease controls. The accuracies of positive and negative predictive values were 48% and 94% respectively. Hence this simple test using economical and indigenous reagents can be applied for the diagnosis of pulmonary and extra-pulmonary tuberculosis.