Accuracy of VIDAS⃝R TB-IGRA in TB patients and individuals with different thresholds of exposure

Objectives: To achieve global TB control, more sensitive and user-friendly diagnostic tools for tuberculosis infection (TBI) are necessary, as it is a potential transmission reservoir. VIDAS® TB-IGRA (bioMérieux) is a fully automated assay recently developed. We report here the results of a global, multi-center, cross-sectional, prospective study to evaluate the diagnostic accuracy of the assay. Methods: Patients with TB disease (n=200) or participants at varying levels of TB exposure risk (n=1460; mixed TB-exposure risk population) were tested with both the VIDAS® TB-IGRA and the QuantiFERON®-TB Gold Plus (QFT®-Plus, QIAGEN). Results: In culture-confirmed TB cases, VIDAS® TB-IGRA had a sensitivity significantly higher than QFT®-Plus (97.5% vs. 80.7%, p<0.0001). Specificity evaluated in blood donors from a low-prevalence country (n = 125) was high for both VIDAS® TB-IGRA and QFT®-Plus (97.6% [93.1-99.5] vs. 95.2% [89.8-98.2]; p=0.083), respectively. In the whole mixed TB-exposure risk population, negative (NPA) and positive percent agreement (PPA) were 90.1% (1097/1217) and 92.1% (223/242), respectively. However, regression analyses revealed that VIDAS® TB-IGRA correlated better with the TB-exposure risk gradient than QFT®‑Plus. Conclusions: Compared with QFT®-Plus, VIDAS® TB-IGRA was significantly more sensitive without a reduction in specificity, and it correlated better with an exposure gradient, suggesting that it is a valuable tool for TBI diagnosis.