More recently, two tests, based on the in vitro release of IFN-γ by circulating lymphocytes (hence, interferon gamma release assays or IGRAs) upon stimulation with the M. tuberculosis-specific antigens early secreted antigenic target, 6 kilodaltons (ESAT-6) and culture filtrate protein 10 kda (CFP-10) (the T-SPOT.TB test-Oxford Immunotec, Oxford, United Kingdom and the QuantiFERON-TB Gold test-QFT-G, Cellestis, Victoria, Australia), have been introduced for the diagnosis of M. tuberculosis infection [10], [11]. The gene discussed is IFNG; the disease is tuberculosis.