Comparison of GeneXpert against Light-Emitting Diode Fluorescent Microscopy for the Diagnosis of Pulmonary Tuberculosis in Addis Ababa, Ethiopia

Abstract

Background: Tuberculosis remains a global health problem despite availability of effective tools. Globally, there were 40% of the 10+ million patients with TB did not get diagnosed or notified. The study was aimed to compare the diagnostic performances of iLED-FM and GeneXpert test for the diagnosis of PTB in Addis Ababa, Ethiopia. Methods: Facility-based cross-sectional study was conducted on a total of 286 sputum samples collected from health centers and hospitals clients with presumptive TB from December 2016 to March 2017. Kappa value, Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of iLED-FM and GeneXpert were calculated against the gold standard. Results: The sensitivity, specificity, PPV and NPV of iLED-FM was 80.15%, 95.48%, 93.75% and 85.06%, for GeneXpert 88.55%, 92.90%, 91.34% and 90.57%, respectively. Kappa value of iLED-FM was 0.765 and 0.817 for GeneXpert. Out of 55 HIV positive presumptive TB patients enrolled in the study, 19 (34.55%) were sputum smear positive by iLED-FM. However, 24 (43.64%) TB cases were detected by GeneXpert. Conclusion: The sensitivity of Xpert MTB/RIF assay was better than iLED-FM in the diagnosis of PTB. It should be implemented as primary diagnostic test in areas where overlapping synergy of TB and HIV/AIDS is high.