The diagnostic value of GeneXpert MTB/RIF of the lapping suspension of the thoracoscopic biopsy tissue in tuberculous pleural effusions

Objective To assess the diagnostic value of GeneXpert MTB/RIF assay using the lapping suspension of thoracoscopic biopsy tissue in detecting tuberculous pleurisy.Methods From January 1, 2017 to December 31, 2017 in the pleurisy ward of Shenyang Chest Hospital, 51 cases who showed unexplained pleural effusion under medical thoracoscopy and were not treated by any anti-tuberculous therapy were selected as the subjects of this study. A routine pathological examination of the pleural biopsy specimen was conducted for each patient. Also, BACTEC MGIT 960 liquid culture system and GeneXpert MTB/RIF detections were conducted using the suspension of the other part of specimen after grinding. The diagnosis accuracy of GeneXpert MTB/RIF assay using biopsy tissue suspension in detecting tuberculous pleurisy was evaluated, taking BACTEC MGIT 960 positive results (stain identification as Mycobacterium tuberculosis) and pleural tissue biopsy results (granulomatous inflammation and anti-acid staining positive) as diagnostic criteria.Results Of the 51 patients, 34 were diagnosed with tuberculous pleurisy. MGIT 960 positive culture and strain identification confirmed 20 cases (39.2%, 20/51), and 17 cases (33.3%, 17/51) were pleural biopsy pathological positive. Among them, 3 cases were confirmed by the two detection me-thods. Seventeen (33.3%, 17/51) patients were diagnosed with non-tuberculous pleural effusion. Taking the finial diagnosis as the gold standard, the sensitivity and specificity of GeneXpert MTB/RIF, MGIT 960 culture system and pathological diagnosis were 64.7% (22/34) and 100.0% (17/17), 58.8% (20/34) and 100.0% (17/17), and 50.0% (17/34) and 100.0% (17/17), respectively. The sensitivity of GeneXpert MTB/RIF was superior to the MGIT 960 culture system and pathological diagnosis; however, the difference was not statistically significant (χ ²=1.53, P=0.466).Conclusion The sensitivity and specificity of GeneXpert MTB/RIF assay using the lapping suspension of thoracoscopic biopsy tissue taken under thoracoscopy is high. It is of great significance for the diagnosis of tuberculous pleurisy.