RAPID DIAGNOSIS OF PULMONARY TUBERCULOSIS BY PHAGE ASSAY IN HIV POSITIVE PATIENTS

Abstract

Tuberculosis is commonest opportunistic infection in HIV positive patients, in India. Rapid progression of tuberculosis in HIV infected patients makes early diagnosis critical.  Though smear microscopy remains the mainstay of diagnosis, has low specificity. Culture techniques are sensitive and specific but are slow while molecular methods are rapid but expensive. Phage amplification which utilizes specific mycobacteriophages to detect viable M.tuberculosis in respiratory samples is simple and rapid.  This study was done to show, comparative evaluation of Phage assay with sputum microscopy and culture on Lowenstein-Jensen media in HIV seropositive patients. Three consecutive sputum samples were collected and subjected to ZN smear. After decontamination and concentration techniques, samples were used for Phage assay, cultured on LJ and smears were prepared. The overall sensitivity, specificity, PPV and NPV of Phage assay when compared to LJ culture was 83.3%,100%,1.0and 0.92 respectively. With respect to smear-negative specimens, the sensitivity was 50%.