The role of bronchoscopy and nucleic acid amplification test in pulmonary tuberculosis diagnosis

Abstract

Introduction: Lisbon has an intermediate incidence of tuberculosis (TB). Flexible bronchoscopy can assist in diagnosing TB in patients with a negative smear microscopy. Earlier diagnosis by means of faster laboratory tests such as nucleic acid amplification tests (NAAT) is essential in controlling disease transmission. Objectives: Analyze the yield of bronchoscopy in diagnosing pulmonary TB and compare smear microscopy, culture and NAAT using GenoType MTBDRplus ver2.0. Methods: A retrospective analysis of TB patients hospitalized in the Infectious Disease’s ward between January 2013 and April 2016 was performed. Patients subjected to flexible bronchoscopy were selected and characterized regarding demographics and microbiological exams. Results: Fifty-eight patients were included with a mean age of 44±19 years and 71% were males. Diagnosis was confirmed by bronchoscopy in 41 (71%). Smear microscopy sensitivity was similar in bronchial wash (BW) and bronchoalveolar lavage (BAL): 39% vs 31%, p value 0.43. Culture sensitivity was also similar in BW and BAL: 70% vs 62%, p value 0.42. Culture sensitivity was superior to smear microscopy in both BW and BAL (BW: 70% vs 39%, p value Conclusion: Bronchoscopy led to diagnosis confirmation in 71% proving its importance in diagnosing pulmonary TB. NAAT sensitivity was similar to culture. NAAT is a faster diagnostic test allowing earlier treatment initiation and contributing to better control disease transmission.