Comparison of GeneXpert MTB/RIF and conventional methods for the diagnosis of tuberculosis in Kosovo

Abstract

Introduction: Tuberculosis (TB) is a major public health problem worldwide, with the highest mortality occurring in developing countries. The burden of TB in Kosovo is among the highest in Europe. The aim of this study was to compare Cepheid GeneXpert MTB/RIF assay for direct detection of Mycobacterium tuberculosis complex (MTBC) and rifampin (RIF) resistance with conventional methods.

Methodology: A cross-sectional design to evaluate diagnostic tests was carried out at the Department of Microbiology, National Institute of Public Health of Kosovo and Lung Clinic, from January to June 2014. The detection of MTBC and RIF resistance using the Xpert MTB/RIF assay was assessed in 116 specimens received from 110 patients suspected of having TB and compared with conventional smear microscopy and culture methods.

Results: Fifty-eight patients (52.7%) were male, and the mean age was 48.6±18.1 years. Twenty-nine patients (26.4%) had underlying lung diseases. Of the 116 specimens investigated, 28 (24.1%) were MTBC-positive by culture, while 34 (29.3%) were positive by Xpert assay. Two samples showed false-negative Xpert results. Compared with culture, the Xpert assay achieved 82.3% (95% 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 rifampin were detected from clinical isolates.

Conclusions: The GeneXpert MTB/RIF assay is a helpful tool for rapid diagnosis and prompt treatment of TB.