Sensitivity of sputum exam with respect to gene expert in detection of MTB at tertiary care hospital

Abstract

Background: According to the WHO Tuberculosis Report 2014, there were 9 million incident cases of TB worldwide, with the South–East Asia and Western Pacific areas accounting for 58 percent of the global burden and India accounting for 24 percent. Aims and Objective: To study Sensitivity of sputum exam with respect to gene expert in detection of MTB at tertiary care hospital Methodology: The present study is an observational cross-sectional study of the patients with pulmonary tuberculosis attending Department of Pulmonary Medicine at a tertiary care centre during period of 1 January 2019 to 30 June 2020 by the permission of Institutional Ethical Committee . Genexpert test / CBNAAT [ Xpert MTB/RIF Assay] Statistical analysis done buy of (version 20) for Windows package (SPSS Science, Chicago, IL, USA). Result: Ziehl and Neelsen staining was done for 200 samples of cases of pulmonary tuberculosis. Out of these 55(27.50%) sputa samples were ZN smear positive and 145(72.50%) were negative. Then all the samples were tested on Gene Xpert MTB/RIF assay. Out of these 200 patients, 186(93%) were MTB detected and 14(7.00%) were MTB not detected. The MTB/RIF assay detect the agent in 54 out of 55 ZN smear positive cases and 132 out of 145 AFB smear negative cases as shown in table No.10. So, MTB detection rate by Gene Xpert 186cases (93.00%) is more as compared to ZN staining 55cases (27.50%). Out of 55 sputum positive cases, 54 were positive for MTB by Gene Xpert but in 01 sputum positive case MTB was not detected by Gene Xpert assay. There was statistically significant better detection with Genexpert when compared to microscopy AFB test in pulmonary tuberculosis patients.The Sensitivity of Sputum was 29.03% and Specificity was 92.86%, Positive Likelihood Ratio4.06, Negative Likelihood Ratio 0.76, Positive Predictive Value (*) was 98.18% and Negative Predictive Value (*) was 8.97%. Conclusion: It can be concluded from our study that the Genexpert is highly sensitive test for the detection of the Mycobacteria and Xpert MTB/RIF assay can quickly identify possible multidrug-resistant TB. From our study we conclude that Gene Xpert MTB/RIF is simple and reliable technique for diagnosing extra pulmonary tuberculosis with high sensitivity and specificity not only in smear positive cases but also in smear negative cases. It is a game changer not only in pulmonary tuberculosis control but probably also in extra pulmonary tuberculosis.