Assessment of diagnostic accuracy of GeneXpert Mycobacterium tuberculosis/rifampicin in diagnosis of pulmonary tuberculosis in Kosovo

Abstract

Background: Despite control program for Mycobacterium tuberculosis (MTB) and anti-tuberculosis (TB) drugs, MTB continues to be a major threat to global health; furthermore, it is the second leading cause of death worldwide. The distribution of TB in Kosovo has the highest rate in Europe. This study was designed to assess the performance of single-sputum GeneXpert MTB/ rifampicin (RIF) assay against the Ziehl-Neelsen smear, solid culture in diagnosing suspected pulmonary cases, and RIF resistance. Methods: A cross-sectional study was conducted to examine various diagnostic methods between 2014 and 2016 in the Department of Microbiology, the National Institute of Public Health, Kosovo, and the Lung Clinic. The present study compares diagnostic methods of MTBC and RIF resistance using Xpert MTB/RIF test in 813 samples from 760 patients suspected of TB by conventional smear microscopy and culture method. Results: Three hundred and ninety-six patients (52.1%) were male and the mean age was 48.6 ± 18.1 years. A total of 261 patients (32.6%) had underlying lung diseases. Of the 801 specimens investigated, 165 (20.5%) were MTBC-positive by culture, while 199 (28.3%) were positive by Xpert assay. Among the examined specimens, Two specimens with false negatives were shown in the Xpert method. Compared with culture, the Xpert assay achieved 82.3% (95% confidence interval [CI]: 65.5%–93.2%) sensitivity and 97.6% (95% CI: 91.5%–99.7%) specificity. GeneXpert could detect 11.7% and 50% additional positive cases as compared to Lowenstein–Jensen culture and smear microscopy, respectively. Three cases with resistance to RIF were detected from clinical isolates. Conclusions: According to the results obtained in this study, GeneXpert MTB/RIF assay can be used as a useful tool for rapid and efficient diagnosis of TB.