VIDAS(R) TB-IGRA accuracy in tuberculosis patients and persons at varying risk of exposure

BackgroundDetection and treatment of individuals with presumed latent tuberculosis (TB) infection (i.e., excluding active disease; LTBI) is imperative to achieve global TB control, as they represent a potential transmission reservoir. However, more sensitive and user-friendly diagnostic tools are needed. MethodsWe evaluated the accuracy for TB infection detection of the new VIDAS(R) TB-IGRA (bioMerieux), a fully automated, single tube (thus eliminating the need for batch testing) overnight incubation assay, compared to the QuantiFERON(R)-TB Gold Plus (QFT-Plus, QIAGEN), in a global multi-centre cross-sectional study (NCT04048018) that included patients with TB disease (n=200) or participants at varying levels of TB exposure (n=1460; mixed exposure-risk-population). ResultsVIDAS(R) TB-IGRA identified TB disease with greater sensitivity than QFT-Plus (97.5% vs. 80.7%, P<0.01%), and yielding significantly fewer false-negatives (2.5% vs. 17.5%; P<0.01%) and indeterminate results (1.0% vs. 9.5%; P=0.02%). In the mixed exposure-risk-population, negative (NPA) and positive percent agreement (PPA) were 90.1% (1097/1217) and 92.1% (223/242), respectively. PPA increased with TB-exposure risk (up to 95.7% for high-risk participants), whereas NPA decreased (starting from 96.9% for low-risk participants). Regression analyses revealed that VIDAS(R) TB-IGRA had a better fit with the risk-exposure gradient than the QFT-Plus. Specificity in extremely low TB-exposure risk participants (n = 125) was high for both VIDAS(R) TB-IGRA and QFT-Plus (97.6% vs. 95.2%; P=8.33%). ConclusionsVIDAS(R) TB-IGRA displayed greater sensitivity than QFT-Plus, had a lower indeterminate rate, correlated better with an exposure gradient, and was highly specific, suggesting that it is a potentially valuable tool for the diagnosis of LTBI. Take-home messageThe first fully automated interferon-{gamma}-release assay--the bioMerieux VIDAS(R) TB-IGRA--is highly specific and displays greater sensitivity than QuantiFERON(R)-TB Gold Plus, and thus represents a valuable new and streamlined diagnostic tool for TB infection.