Abstract:
BD Probe Tec ET, a fully automated system for nucleic acid amplification by strand displacement amplification (SDA) technique. Target sequence for amplification is lS6110 gene of M. tuberculosis, and the amplification is detected by fluorescent energy transfer after hybridization of capture probe. Between February 2002 and January 2004, 70 patients with symptomatic exudative lymphocytic pleural effusion were enrolled in our study to evaluate the diagnostic sensitivity and specificity of BDProbeTec ET assay. The mean age was 51.37 years (range: 15 to 82 years). There were 45 men and 25 womans. Pleural fluid from all patients was sent for AFB staining, culture of Mycobacterium tuberculosis on ogawa media and with MGIT 960 Automated System and cytology. In addition, it was sent for fluid was sent for BDProbeTec ET assay. Histopathological examination was also performed on two pleural biopsies specimens. A diagnosis of neoplasm and tuberculous effusion was obtained in 29 cases (41.4 %) and 41 cases (58.6 %), respectively. Tuberculous pleuritis was categorized in to 3 groups including a definite (13 cases), probable (13 cases) or possible (15 cases) group. The overall sensitivities, specificities, positive and negative predictive values were 14.6, 100, 100 and 45.3, respectively for AFB staining; 17.1, 100, 100 and 46 % respectively for pleural fluid culture; 12.2, 100, 100 and 40.9 %, respectively for pleural histopathological examination; and 53.7, 100, 92.3 and 60.4 %, respectively for BDProbeTec ET assay of pleural fluid. If only 13 cases of definite tuberculous pleuritis were analysed, the sensitivity and specificity of BDProbeTec ET assay were 92.4 and 100 %, respectively.