Detection of Mycobacterium tuberculosis by polymerase chain reaction in 301 biological samples--a comparative study.

A repetitive target sequences of Mycobacterium tuberculosis DNA was amplified by polymerase chain reaction (PCR) in a total of 301 clinical samples. Sputum, blood, pleural fluid, and bronchial lavage specimen were taken from clinically suspected causes of tuberculosis and processed for the diagnosis of tuberculosis using a simplified procedure of DNA extraction. PCR was positive in a total of 58 samples (58/301--19.3%). A significant number of smear and culture negative cases of tuberculosis were PCR positive (37/174--21.26%). This finding, combined with the absence of either false positive or false negative results reflects the greater usefulness of this technique.