In our study, serum IFNγ levels could discriminate between sarcoidosis and TB (Youden's index = 0.64, sensitivity = 78 %, specificity = 86 %, and AUC = 0.785) as well as between SU and TBU (Youden's index = 0.61, sensitivity = 69 %, specificity = 92 %, and AUC = 0.769). Here, IFNG is linked to tuberculosis.