GeneXpert analysis of bronchoalveolar lavage (BAL) samples: promising diagnostic modality in patients with smear-negative pulmonary tuberculosis

Purpose: The aim of the study is to assess the diagnostic utility of bronchoalveolar lavage (BAL) samples with GeneXpert test in diagnosis of TB in smear-negative patients. Method: One-hundred sixty-nine cases were included in this study, as they had a radiological finding suggested to have pulmonary tuberculosis, while the sputum direct smear examination for acid-fast bacilli was negative. All cases prepared to do fiber-optic bronchoscope with bronchoalveolar lavage collection after their consent and post bronchoscope sputum collection for further molecular and microbiological examination. Results: The combined diagnostic yield of all bronchoscopy procedures was 15.97% (27 cases of 169) and the final diagnosis of TB cases was established in 16 cases of 169 (9.4%) using BAL culture and in 20 cases of 169 (11.83%) by GeneXpert methods. Post bronchoscope direct sputum examination, culture, and GeneXpert evaluation gave diagnostic yield about 1.1%, 5.5%, and 7.1%, respectively. The specificity of GeneXpert examination of BAL and post bronchoscope sputum was 95.42% and 97.38%, respectively. Conclusion: Early detection of pulmonary tuberculosis using fiber-optic bronchoscope BAL examination and post bronchoscope sputum with GeneXpert method promotes the accurate decision to start antituberculous therapy in patients with smear negative.