IFNG and tuberculosis: In TB patients, the IFN-γ concentrations in the QFT assays (median, 6.79; interquartile range [IQR], 1.70–10.85 IU/mL) were higher than those measured by ESAT-6–free IGRA (median 4.27; IQR, 1.59–9.51 IU/mL; P = .005), while equivalent and extremely low IFN-γ concentrations were measured in M.tb-unexposed individuals (Figure 2B).