Efficacy of Cb-Naat in Detecting Sputum Negative Pulmonary Tuberculosis

Abstract

BACKGROUND Tuberculosis (TB) is a major health problem in India. The World Health Organization has recently in 2010 endorsed the GeneXpert MTB/RIF assay for rapid detection of smear negative and multidrug-resistant tuberculosis. The aim of the study is to evaluate the role of Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) in sputum AFB negative Pulmonary Tuberculosis (PTB). MATERIALS AND METHODS This is an observational study conducted in the Department of Pulmonary Medicine, RRMCH, Bengaluru, between August 2016 to June 2017. Patients who presented with symptoms and signs suggestive of pulmonary tuberculosis, chest x-ray showing features of pulmonary tuberculosis were included in the study whose sputum for AFB was negative. Sputum/BAL samples from these patients were sent for CBNAAT. RESULTS CBNAAT was done for 80 samples of the patients who were having history and CXR suggestive of pulmonary tuberculosis with sputum AFB negative. Out of these 80 sputum-AFB negative samples, 29 (36%) were CBNAAT positive. Most of the cases were men aged >50 yrs. Most diabetics (78%) were CBNAAT positive. Most diabetics had HbA1C >10. Most diabetics had lower zone infiltrates on CXR. CONCLUSION Because of its simplicity, rapidity and sensitivity, this seems to be a very novel tool for diagnosis of extrapulmonary tuberculosis from clinical samples and that it should be researched more thoroughly.