Diagnostic performance of GeneXpert MTB/RIF assay compared to conventional methods and its clinical correlation in tuberculosis management: A retrospective study from Puducherry, South India
DOI:
https://doi.org/10.31305/rrijm.2025.v10.n9.021Keywords:
Mycobacterium tuberculosis (MTB), GeneXpert MTB/RIF assay, diagnostic performance, clinical profile, tuberculosis diagnosis, Puducherry, South IndiaAbstract
Background: Wide variations in tuberculosis prevalence and drug resistance necessitate region-specific data-based protocols for accurate diagnosis and management. This study aimed to compare the diagnostic performance of three diagnostic microbiology tests for diagnosing tuberculosis (GeneXpert, MTB/RIF assay, sputum microscopy, and culture) in clinically suspected tuberculosis subjects, and correlate the results, especially GeneXpert positivity, with the clinical profile, risk factors, and outcomes, in our setting. Methods: This retrospective quantitative study was conducted between February and June 2017 at a tertiary care teaching institution in Puducherry, South India. Revised National Tuberculosis Control Program protocols were followed for diagnostic microbiology tests, and clinical profiles were extracted and collated. Tests of diagnostic performance, and risk factor variable correlation with GeneXpert tuberculosis detection was performed using SPSS 21.0 p value<0.05 considered statistically significant. Results: Of the 114 recruited subjects, GeneXpert detected tuberculous bacilli in 19(16.67%), culture in 2(1.75%), and microscopy in 10(8.77%) suspects. With GeneXpert considered the gold standard, the specificity and positive predictive value were 100% each, the sensitivity was 10.53% and 52.63%, and the diagnostic accuracy was 81.21% and 90.05% for culture and microscopy, respectively. A history of tuberculosis, clinical diagnosis of tuberculosis, suggestive chest X-ray findings, Diabetes Mellitus, smoking and alcohol use, rifampicin resistance, and higher mortality were each significantly associated with GeneXpert positivity (p <0.005). Conclusion: Our study provides vital region-specific information on the diagnostic performance of microbiological tests for tuberculosis diagnosis, together with prevalence rates of important risk factors and treatment outcome variables, to help formulate appropriate management strategies in this setting.
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