IFNG and tuberculosis: Currently, two commercial systems are available: the QuantiFERON-TB Gold in-tube assay (QFT-GIT; Cellestis, Carnegie, Australia) that also includes a third antigen TB7.7 and measures IFN-γ using an ELISA method; the TSPOT.TB assay (Oxford Immunotec, Abingdon, UK) that quantitates IFN-γ-producing cells with the enzyme-linked immunospot (ELISPOT) technique.