When true infection was strictly defined using M. bovis cultures (n = 53), normally used as a gold standard test to evaluate diagnostic tools, gross/ microscopic examination showed the highest Se (46/53, 86.8%), followed by the IFN-γ assay (44/53, 83.0%), IS1081 PCR (36/53, 67.9%), IS6110 PCR (30/53, 56.6%), CFT (29/53, 54.7%), and acid-fast staining (24/53, 45.3%). Here, IFNG is linked to infection.