GENE-XPERT gives early diagnosis in early tuberculosis

Abstract

Introduction: Gene-Xpert, a CBNAAT (catridge based nucleic acid amplification test) is a widely accepted diagnostic test for Tuberculosis. This test is a rapid diagnostic test for Tuberculosis detection as well as Rifampicin resistance in direct smear negative cases. Due to of non availability and lack of cost effectiveness it is still not common in devoloping countries like India.

Aims and Objective: To compare the Gene-Xpert result with sputum smear microscopy and culture report.

Methods: This was a prospective study conducted from July 2014 to June 2015.Bronchial washings, sputum,pleural samples(pleural fluid,pleural biopsies),tissue biopsy and other samples from patients of suspected Tuberculosis were sent for direct smear/culture for AFB as well as Gene-Xpert.

Results: A total of 415 samples were analysed, among which 163 was Bronchial washings ,71 were Sputum,Pleural samples was 98 and others ( biopsies / FNAC and body fluids) were 83.Gene-Xpert was detected positive in 67 samples (BAL-30,Sputum-15,Pleural samples-4,Others-18). Rifampicin resistence was detected in 15 samples and 2 samples had indeterminate result. Of the 67 patients who had detected positive in Gene-Xpert, 28 samples were positive for direct smear and 40 samples had shown growth of AFB in culture. Only one sample(sputum) in 415 show AFB in direct smear but was negative for Gene-Xpert .Culture growth for mycobacterium tuberculosis was seen positive in 7 which were negative in Gene-Xpert.

Conclusion: Gene Xpert is an excellant clinical tool for detection of Mycobacterium Tuberculosis in early stage where the direct smear is negative as well as in early detection of Rifampicin resistance.