IFNG and tuberculosis: Commercial Interferon gamma (IFN-γ) release assays (IGRAs) such as the ELISA-based Quantiferon TB Gold In-Tube assay (QFT-IT; Qiagen, Germany), and the ELISPOT-based T SPOT.TB (Oxford Immunotec, UK), are widely used especially in high income, low burden settings for the diagnosis of M.tb infection and for research in high-burden TB settings.