VIDAS®TB-IGRA accuracy in tuberculosis patients and persons at varying risk of exposure

Abstract

ABSTRACTBackgroundDetection 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®TB-IGRA (bioMérieux), a fully automated, single tube (thus eliminating the need for batch testing) overnight incubation assay, compared to the QuantiFERON®-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®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®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®TB-IGRA and QFT-Plus (97.6%vs. 95.2%;P=8.33%).ConclusionsVIDAS®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-γ-release assay—the bioMérieux VIDAS®TB-IGRA—is highly specific and displays greater sensitivity than QuantiFERON®-TB Gold Plus, and thus represents a valuable new and streamlined diagnostic tool for TB infection.