Utility of PCR in bronchial aspirate samples for rapid diagnosis of tuberculosis

Abstract

Introduction: Rapid diagnosis and treatment are important for preventing transmission of Mycobacterium tuberculosis. Objective: To study the yield of polymerase chain reaction (PCR) in samples of bronchial aspirate (BA) for rapid diagnosis of pulmonary tuberculosis (TB). Methods: We retrospectively reviewed TB-suspected patients requiring diagnostic bronchoscopy between 1st February 2012 and 1st October 2013. PCR assay and smear microscopy were performed in BA in all cases. We compared the sensitivity and specificity of both methods for early diagnosis of tuberculosis. Definitive diagnosis of TB was established based on a positive culture for Mycobacterium tuberculosis in respiratory samples (sputum culture, BA, bronchoalveolar lavage) and/or the presence of necrotizing granulomas in lung biopsy and response to treatment of TB. Results: 168 patients were included, 118 men (70.2%). Mean age was 63.6 ± 14.5 years. Eighteen patients (10.7%) were diagnosed with TB. Table 1 shows the results of PCR and smear microscopy in BA in the groups of patients with and without TB The sensitivity and specificity of PCR was 88.8% and 99.3%, respectively. The sensitivity and specificity of smear microscopy was 55.5% and 99.3%, respectively. Conclusions: The sensitivity of PCR for rapid diagnosis of tuberculosis in BA samples was higher than smear microscopy. Including this test as a diagnosis tool in daily clinical practice could be very useful for the early detection of TB.