Comparative analysis of genexpert and line probeassay for detecting mycobacterium tuberculosis at the national tuberculosis control center inNepal

Abstract

Tuberculosis is a disease caused by Mycobacterium tuberculosis; a pathogenic bacterial species primarily known for causing chronic respiratory infections. In Nepal, tuberculosis (TB) remains a critical public health challenge, highlighting the urgent need for effective and rapid diagnostic tools. This study is important as it evaluates the effectiveness of GeneXpert and Line Probe Assay (LPA) compared to the culture method, potentially enhancing rapid TB detection and improving patient management. This hospital-based cross-sectional study was conducted from September 2022 to April 2023 at the National Tuberculosis Control Centre. The objective was to evaluate the diagnostic capabilities of GeneXpert and Line Probe Assay (LPA) for detecting Mycobacterium tuberculosis compared to the culture method, which is considered the gold standard. The research method involved collecting and analyzing sputum samples (n=398) using solid culture, GeneXpert and LPA. The culture method identified Mycobacterium tuberculosis in 128 cases. GeneXpert detected it in 129 cases, while LPA detected it in 123 cases. Against culture, GeneXpert demonstrated a sensitivity of 95.49% and a specificity of 99.22%, with results available in approximately 2 hours. The positive predictive value for GeneXpert was 98.45%, and the negative predictive value was 97.70%. In comparison, LPA showed a sensitivity of 90.98% and a specificity of 99.18%, with a turnaround time of up to 6 hours. The positive predictive value for LPA was 98.37%, and the negative predictive value was 95.29%. Additionally, Cohen's Kappa value for GeneXpert was 0.95, and for LPA, it was 0.92, indicating almost perfect agreement with the culture method. The findings suggest that GeneXpert offers higher sensitivity and faster results, making it valuable for rapid TB detection. Both assays exhibited high specificity, supporting their integration into routine TB diagnostics. This enhances rapid and accurate detection, thereby improving patient management and treatment outcomes. Keywords: Mycobacterium tuberculosis, Tuberculosis, GeneXpert, Line Probe Assay, Culture