Diagnostic accuracy of the novel and biosafe molecular assay Orange G3 TBC compared to GeneXpert for tuberculosis diagnosis in resource-limited settings

Background: Tuberculosis (TB) remains a global public health priority, with 10.5 million new cases and 1.5 million deaths reported in 2023. Current diagnostic methods face limitations in sensitivity, biosafety, and accessibility, particularly in low-resource settings. Objective: This study evaluates the diagnostic accuracy of a novel, Polymerase Chain Reaction (PCR) platform (Orange G3 TBC), comparing it with the WHO-endorsed GeneXpert Ultra system in Oruro, Bolivia. Design: We conducted a randomized, double-blind study. Methods: The study included 71 clinical samples (67 sputum samples and 4 cerebrospinal fluid samples) from patients with presumptive TB. All samples were tested with GeneXpert Ultra and the Orange G3 TBC platform, which incorporates a unique biosafe processing system. Statistical analysis included sensitivity, specificity, predictive values (positive predictive value (PPV) and negative predictive value (NPV)), likelihood ratios (LR+ and LR-), and correlation measures. Results: Orange G3 TBC demonstrated strong performance metrics compared to GeneXpert Ultra: sensitivity = 90%, specificity = 97%, diagnostic efficiency = 96%, PPV = 82%, and NPV = 98%. Statistical analysis showed a high correlation between the two methods (Pearson's correlation = 0.834, Kappa = 0.832, LR+ = 27.3, LR- = 0.103). Conclusion: The Orange G3 TBC platform offers comparable diagnostic accuracy to GeneXpert Ultra. The system is adaptable to resource-limited settings, making it a viable alternative for TB diagnosis in endemic regions.