ROLE OF GENE XPERT AND LIQUID CULTURE IN DIAGNOSIS OF EXTRA PULMONAR TUBERCULOSIS

Abstract

INTRODUCTION: Extrapulmonary Tuberculosis (EPTB) accounts for 15- 25% of all TB cases. It is more difficult to diagnose than Pulmonary tuberculosis and often requires invasive procedures to obtain tissue and or fluid samples. Histology is time-consuming and establishing a diagnosis of TB with high specificity remains difficult. Tissue smear microscopy after special staining is often negative. Tissue culture often leads to considerable delays compromising patient care and outcomes. AIMS AND OBJECTIVES:1. To diagnose Extra Pulmonary Tuberculosis by Gene Xpert(Xpert MTB/Rif assay or CBNAAT) and Liquid Cultures. 2. To evaluate the Sensitivity and Specificity of Gene Xpert in Extra Pulmonary Tuberculosis in comparison with Liquid Culture MGIT960 system. MATERIALS AND METHODS: This retrospective cross-sectional study was carried out by reviewing all suspected extra pulmonary tuberculosis samples of 430 patients attending OPD at Institute of Respiratory Diseases, Jaipur from April 2020 to March 2021.The extrapulmonary samples (pleural fluid,CSF,pus,BAL,Ascitic fluid,Synovial fluid,Gastric aspirate,Liver aspirate) were subjected to GeneXpert and Liquid culture MGIT960 system. RESULTS: Of the 430 Extra Pulmonary Samples, The Sensitivity and Specificity of CBNAAT was 79.77% and 95.30% respectively in comparison with Liquid Culture. Out of the 430 Samples CBNAAT was Positive in 87 samples of which 71(81.60%) were Rifampicin sensitive and 16(18.39%) were Rifampicin Resistant.Out of the 430 Samples,Liquid cultures was Positive in 89 samples. CONCLUSION: Gene Xpert has a notable advantage of detecting tuberculosis within two hours which is acceptable to all clinicians to institute early treatment.CBNAAT is one of the rapid diagnostic tests available in the country and it should be routinely used under the public and private health sector effectively to detect early tuberculosis in Extra Pulmonary Samples.