IFNG and tuberculosis: There are several diagnostic and screening assays for tuberculosis (TB) infection (TBI) including the tuberculin skin test (TST) and interferon gamma release assays (IGRAs), which include the QuantiFERON-TB Gold in-tube (QFT-G) (QIAGEN, Germantown, MD, USA) and T-SPOT.TB (Oxford Immunotec, Inc., Marlborough, MA, USA) assays.