Comparison of induced sputum and bronchial washings for CBNAAT in diagnosing sputum smear negative pulmonary tuberculosis

Abstract

Introduction: Tuberculosis is one of the most infectious public health problems for decades and has also become difficult to diagnose in recent times due to association with immunocompromised status. With the advent of the newer diagnostic technique like CBNAAT, can providing positive results even in less number of tuberculos bacilli in specimen samples. The present study was aimed to compare induced sputum and bronchial washings for CBNAAT in diagnosing sputum smear negative tuberculosis. Materials and Methods: A prospective, observational study was conducted in the Department of Pulmonary Medicine, Maharaja Institute of Medical Sciences (MIMS), Vizianagaram, Andhra Pradesh, India. A total of 43 patients with sputum negative tuberculosis were enrolled and induced sputum and BAL fluid for CBNAAT sent for analysis under RNTCP in district hospital. Results: Male patients (67.45%) were more compared to the females (32.55%). Majority belongs to 51-60 years with mean age group of 49.18 years. Most common X- ray presentation was infiltration followed by consolidation. Induced sputum CBNAAT was positive in only 07 patients compare d to bronchial washings CBNAAT in 27 patients. Conclusions: As CBNAAT can diagnose rapidly and prevent transmission and mortality in smearnegative in pulmonary tuberculosis patients, all smear-negative and immunocompromised patients should be subjected to CBNAAT. CBNAAT detects pulmonary TB in PLHIV with greater efficacy than sputum microscopy, also helping in early diagnosis in less than 2 hours, so that early therapy can be started, thus decreasing the incidence of MDR-TB and associated its mortality. Keywords: Bronchial washings, CBNAAT, Induced sputum, Pulmonary tuberculosis, Smear negative.