IFN-γ release assays (IGRA’s) These in vitro blood assays based on IFN-γ production from sensitized T cells TB antigens like early secretory antigenic target 6 (ESAT 6) and culture filtrate protein 10 (CFP 10), are commercially available as QuantiFERON-TB QFT), Enhanced QuantiFERON-TB Gold assay and ELISPOT format, T-SPOT-TB assay] [5]. The gene discussed is IFNG; the disease is tuberculosis.