Commercial polymerase chain reaction test (Amplicor set) in the diagnosis of smear-negative pulmonary tuberculosis from sputum and bronchoalveolar lavage.

The study presents experience with polymerase chain reaction (PCR) in the diagnosis of tuberculosis (TB) and compares the results obtained in sputum and bronchoalveolar lavage fluid (BALF). A total of 1,097 samples from 846 smear-negative patients with suspected TB was examined using PCR and culture during a period of 40 months. TB was the final diagnosis in 160 patients, based on the evidence of mycobacteria in 90 patients and on clinical criteria in the remaining 70. The PCR test had high specificity (98% and 99%, respectively) but poor sensitivity (37% and 34%, respectively) regardless of whether sputum or BALF was examined. Surprisingly, the sensitivity of culture (44% and 35% in sputum and BALF, respectively) was higher than that of PCR in this group. The contribution of BAL to establishing the diagnosis of tuberculosis was rather limited, yet substantial in some patients. The results obtained in this study were compared with the results published in the literature, and it was concluded that further clinical studies are necessary to establish an appropriate role for the polymerase chain reaction in the diagnosis of tuberculosis.