The diagnosis of tuberculosis may depend on examination of the sputum, examination of the plewal fluid for Mycobacterium tuberculosis, and histopathological examination of the parietal pleura, still in many cases, there is no conclusive proof for the diagnosis. The present study aimed at evaluating the role of the polymerase chain reaction (PCR) in the diagnosis of different forms of tuberculosis from different tissue samples and buffy coat of the peripheral blood. This study included 37 patients, divided into three groups. Group I included 20 patients with active tuberculosis sputum smear and/or culture positive for acid fast bacilli. Group II included 13 patients with unilateral tuberculousplewal effusion with highly positive tuberculin test and exudative lymphocytic plewal effusion. The diagnosis was confirmed by culture of the plewal fluid on L.J. media, also by histopathological examination for caseatingtuberculous granuloma of'the parietal plewal biopsy. Group III included 4 patients with right side transudativeplewal effusion secondary to congestive heart failure. Sputum PCR was positive in 18 out of 20 patients in group I but negative in all cases of group II and III (sensitivity 90.9% and specificity 100%). Plewal fluid PCR was positive in 10 patients out of 13 cases in group II but negative in group III (sensitivity 81.2% and specificity 100%). Peripheral blood PCR was negative in all patients of the three groups (sensitivity zero% and specificity 100%). From this study if can be concluded that PCR is a useful, sensitive, specific and rapid technique for the diagnosis of tuberculosis from the tissue samples of the affected organ and not from the peripheral blood. |
