IFNG and tuberculosis: Interferon gamma (IFN-γ) release assays (IGRAs), such as the QuantiFERON-TB Gold test (QFT-G) and QuantiFERON-TB Gold In-Tube test (QFT-GIT) are being used as substitutes for the tuberculin skin test (TST) to detect M. tuberculosis (Mtb) infection with increasing frequency [1]–[3].