Consistent with a recent study reporting a lower sensitivity of the T-SPOT.TB assay for diagnosis of extra-pulmonary TB compared with PTB (Wang et al., 2015), we also observed a lower magnitude of IFN-γ responses in patients with extra-pulmonary TB than in those with PTB (Figure 3A), which resulted in the higher positive rate in PTB cases (84.75%) than in EPTB cases (64.86%; Table 2). Here, IFNG is linked to tuberculosis.