In this respect, the two commercially available interferon-(IFN)-γ release assays (IGRAs) QuantiFERON®-TB Gold In-Tube (QFT; Cellestis/QIAGEN, Hilden, Germany) and T-SPOT®.TB (T-SPOT; Oxford Immunotec, Abingdon, UK) possess distinct advantages. The gene discussed is IFNG; the disease is tuberculosis.