Culture for Mycobacterium tuberculosis(M. tuberculosis) is important for tuberculosis control, so is the need for a rapid, simple and inexpensive identification test for mycobacterial culture isolates. The laboratories under Revised National Tuberculosis Control Programmes (RNTCP) in India are being scaled up by the introduction of rapid broth based culture systems. Laboratory mycobacterial culture isolates have to be further identified as M. tuberculosis or Non Tuberculous Mycobacteria (NTM) since accurate identification of M. tuberculosis complex is mandatory for appropriate diagnosis and treatment of tuberculosis. Biochemical tests are slow and sometimes require subcultures, as M. tuberculosis complex take weeks to grow. Capilia TB test is an immumno-chromatographic assay using monoclonal antibodies to detect MPB64 antigen/protein which is specific for M. tuberculosis complex (MTC). Therefore, the usefulness of Capilia TB test for culture confirmation of M. tuberculosis complex was evaluated in 75 mycobacteria positive clinical isolates by comparing it with conventional biochemical identification tests. The overall sensitivity and specificity was found to be 96.7 and 100%, respectively. The turn-around time for capilia ranged from 9-16 days as compared to biochemical identification which was 30-70 days. Capilia TB test is simple to perform and provides rapid confirmation of M. tuberculosis complex with minimal investment in terms of infrastructure, human labour and expertise. Laboratories using liquid culture may consider Capilia TB for rapid identification of M. tuberculosis complex.
Jyoti Arora, Ritu Singhal, Manpreet Bhalla, Shakir Reza, Potharaju Visalakshi, Digamber Behera and Vithal Prasad Myneedu, 2012. Diagnostic Utility of Capilia TB Assay for Identification of Mycobacterium tuberculosis Complex. Current Research in Tuberculosis, 4: 13-18.