Diagnostic Accuracy of Xpert MTB Compared to Smear Microscopy in Pulmonary vs Extrapulmonary Tuberculosis

ABSTRACT

Introduction: Mycobacterium tuberculosis is the mostsignificant infectious disease causing death worldwide.Inability to rapidly diagnose and treat the affected patientsleads to increased morbidity and mortality, developmentof secondary resistance. There is sparse data which showthe accuracy of diagnosis of tuberculosis by Gene Xpert inpatients. There is limited data on the usefulness of XpertMTB in the diagnosis of extrapulmonary TB. Study aimedto evaluate the diagnostic accuracy of XpertMTB comparedto smear microscopy in pulmonary and extra pulmonarytuberculosis.Material and methods: Prospective observational studyconducted from May 2017 to July 2017. The study wasconducted in Department of medicine, Department ofpulmonology at R.L.Jalappa hospital and research centre,Kolar. 139 tubercular suspects who were not human immunedeficiency virus (HIV) positive were included in the study.Result: Out of 139 patients 72 were males and 67 were females.99 pulmonary samples and 40extrapulmonary samples wereobtained. 93 pulmonary samples and 24 extrapulmonarysamples were culture positive. Smear microscopy has lowersensitivity in diagnosing pulmonary TB (46.2%) as well asextrapulmonary TB(16.6%).Conclusion: The Xpert MTB is a rapid, sensitive and areliable diagnostic test for TB than smear microscopy in bothpulmonary as well as extra pulmonary TB. The diagnosisof extrapulmonary TB should not solely depend on theresults of Xpert MTB and should be subjected to culture ofMycobacterium.