Interferon-gamma (IFN-γ) release assays (IGRAs), such as T-SPOT.TB, QuantiFERON-TB Gold Test (QFT-GT), are more specific and are based on the T cell mediated IFN-γ release after stimulation with specific Mycobacterium tuberculosis (M.TB) antigens. The gene discussed is IFNG; the disease is tuberculosis.