Evaluation of PCR based test for the detection of Mycobacterium tuberculosis in coded sputum specimens

A test based on amplification of 169 bp DNA specific to Mycobacterium tuberculosis was evaluated in a trial, on 50 coded samples which included 25 sputum specimens from radiologically, clinically and bacteriologically proven patients of pulmonary tuberculosis and 25 control specimens. At the end of the trial the code was broken and the results of PCR test were compared with those obtained with Ziehl Neelsen staining and culture test. The test appeared highly sensitive reacting 100 per cent in either of the hands with concordance rate of 76 per cent; 3 of 25 control samples gave false positive results.