Accuracy of VIDAS<sup>Ⓡ</sup> 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, multicenter, 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 Ⓡ 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.