EVALUATION OF GENEXPERT VERSUS CONVENTIONAL DIAGNOSTIC METHODS FOR DETECTION OF PULMONARY AND EXTRA-PULMONARY TUBERCULOSIS

Abstract

Introduction: Tuberculosis (TB) remains a major global health challenge, necessitating rapid and accurate diagnostic methods. While conventional techniques like acid-fast bacilli (AFB) smear and culture are widely used, their limitations in sensitivity and turnaround time highlight the need for more efficient tools. The GeneXpert MTB/RIF assay offers a molecular-based solution for the simultaneous detection of Mycobacterium tuberculosis and rifampicin resistance. Objectives: This study aimed to evaluate the diagnostic accuracy of GeneXpert in comparison to AFB smear and fluorescent staining, focusing on their sensitivity, specificity, and overall diagnostic performance. Material and Methods: This prospective cross-sectional study was conducted at Mahaban Medical and Research Hospital, Topi, District Swabi. A total of 227 samples (115 males and 112 females) were analyzed, categorized by age and sample type (pulmonary and extra-pulmonary). All samples underwent diagnostic testing with GeneXpert, AFB smear, and fluorescent staining. Results: Of the 227 samples, 36 (15.85%) were positive for M. tuberculosis, comprising 19 (52.77%) pulmonary and 17 (47.3%) extra-pulmonary specimens. The most affected age group was 1-20 years (36.11%). The GeneXpert assay demonstrated a sensitivity of 97.2%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 99.5%. In comparison, AFB smear showed sensitivity, specificity, PPV, and NPV of 72.2%, 99.5%, 96.3%, and 95.02%, respectively, while fluorescent staining showed corresponding values of 83.33%, 98.96%, 93.75%, and 97.44%, respectively. The incidence of rifampicin resistance was 2.8%, detected in one sputum sample by GeneXpert. Conclusion: GeneXpert demonstrates superior sensitivity and specificity compared with conventional smear microscopy. Its ability to rapidly and accurately detect both M. tuberculosis and rifampicin resistance makes it an invaluable tool for the timely diagnosis and effective management of tuberculosis. Incorporating GeneXpert into routine diagnostic protocols can significantly enhance TB control efforts