IGRAs measures the amount of interferon gamma (IFN gamma) released after stimulation of lymphocytes with tuberculous antigens ESAT-6 and CFP-10 (QuantiFERON -TB - Gold in Tube) or by counting, after such exposition, stimulated lymphocytes producing IFN gamma, (T-Spot.TB) [9–12]. Here, IFNG is linked to tuberculosis.