| ORIGINAL ARTICLE |
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| Year : 2009 | Volume
: 27
| Issue : 2 | Page : 134-138 |
Clinical evaluation of the mycobacteriophage-based assay in rapid detection of Mycobacterium tuberculosis in respiratory specimens
S Prakash, SK Katiyar, S Purwar, JP Singh
Department of Tuberculosis and Respiratory Diseases, GSVM Medical College, Kanpur - 208 002, India
Correspondence Address:
S Prakash
Department of Tuberculosis and Respiratory Diseases, GSVM Medical College, Kanpur - 208 002
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0255-0857.49426
Context: Search for a cost-effective, rapid and accurate test has renewed interest in mycobacteriophage as a tool in the diagnosis of tuberculosis (TB). There has been no reported data on the performance of phage assay in a high burden, low-resource setting like Kanpur city, India. Aims: To assess the sensitivity and specificity of the FASTPlaque TB™ kit ability to impact the bacillary load in the phage assay and its performance in the sputum smear sample negative cases. Materials and Methods: The study involved a cross-sectional blinded assessment of phage assay using the FASTPlaque TB™ kit on 68 suspected cases of pulmonary TB against sputum smear microscopy by Ziehl-Neilsen staining and culture by the LJ method. Results: The sensitivity, specificity and positive and negative predictive values of the phage assay were 90.7, 96, 97.5 and 85.7%, respectively. The assay was negative in all the five specimens growing mycobacteria other than TB. The sensitivity of the phage assay tended to decrease with the bacillary load. Of the smear-negative cases, three were false negative, and all of which were detected by the phage assay. Smear microscopy (three smears per patient) had a sensitivity and specificity of 93 and 64%, respectively. Conclusions: The phage assay has the potential clinical utility as a simple means of rapid and accurate detection of live Mycobacterium tuberculosis bacilli; however, its performance has been inconsistent across various studies, which highlights that the assay requires a high degree of quality control demanding infrastructure and its performance is vulnerable to common adversities observed in "out of research" practice settings like storage, transport and cross-contamination.
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