Use of more specific antigens such as ESAT‐6/CFP10 in the IFN‐γ test may offer additional diagnostic power in herds with animals vaccinated with BCG (van Pinxteren, Ravn, Agger, Pollock, & Andersen, 2000) and/or known co‐infection with other mycobacteria (Aagaard et al., 2010). The gene discussed is IFNG; the disease is coinfection.