IFNG and tuberculosis: Commercially available IFN-γ release assays (IGRAs) measuring the IFN-γ concentrations released after a 24 hrs in vitro stimulation of whole blood with peptides from antigens encoded in the RD-1 region of the Mtb genome can identify LTBI subjects [11], but they were reported to lack sensitivity [12]–[14], and they provide no clue as to the risk for reactivation TB [15], [16].