contribution of the xpert mtbrif to the etiological diagnosis of tuberculous pleurisy introduction performance of the xpert mtbrif for the detection of mycobacterium tuberculosis in pleural liquid is poorly described the aim of this study was to determine its usefulness for the etiological diagnosis of a tuberculous pleurisypatients and method we performed a descriptive crosssectional study with analytical design including all the patients having a unilateral serofibrinous pleurisy exudative lymphocytic and sterile the diagnosis of pleural tuberculosis was considered based on epidemiological clinical paraclinical and therapeutic arguments the xpert mtbrif of the pleural fluid was carried out among all patientsresults pleural tuberculosis was confirmed in 301 patients the median age was 32years our study has included 217 men 721 with a final sex ratio of 26 the cost of the pleural biopsy coupled with histology made it practicable in only 90 patients 299 with a yield of 80 the xpert mtbrif of the pleural liquid was positive in only 10 patients 33 of the casesconclusion gene amplification by xpert mtbrif of the pleural liquid is much less effective in establishing the diagnosis of tuberculous pleurisy than pleural biopsy which remains the gold standard