A Comparison Study of CBNAAT, Gene Xpert and Line Probe Assays in the Diagnosis of Tuberculosis in smear Negative Specimens

Abstract

Tuberculosis (TB) is a serious and important public health issue to be addressed in India. Timely diagnosis of the drug resistance in tuberculosis is essential to ensure and initiate appropriate therapy. The detection of drug resistant Mycobacterium tuberculosis (MTB) in cases of smear-negative and clinical diagnosed pulmonary TB. A prospective case-control study was conducted on 473 pulmonary samples received at the tertiary care center from January 2019 to December 2019. All specimens were processed for microscopy and culture. CBNAAT- Gene Xpert and LPA Genotype MTBDRplus (VER 2.0) was used to confirm in smear-negative samples. Among the pulmonary samples, 52% smear-positive, and 48% smear-negative, 183 (43%) were found to be culture-positive by Lowenstein Jensen medium (LJ) and MGIT 960, 267 (63%) were positive CBNAAT and LPA n= 216 (51%) samples positive for the TUB band. The use of CBNAAT-Gene Xpert, Line Probe Assay Genotype MTBDR plus(VER 2.0) can be done from the samples directly and the diagnostic performance are more specific for detecting MTB in smear-negative specimens. This study suggests that LPA also helps in the diagnosis of MDR rapidly and in initiation of earlier treatment.