When serum level of MIF was increased by 1 ng/ml, the unadjusted risk for drug-resistant TB would be increased by 8% (OR: 1.08 [95% CI: 1.03–1.14], P = 0.002); and the adjusted (including age, cavitary lesion, pleural effusion, disseminated, ALB, CRP, WBC and IL-6) risk would be elevated by 4% (OR: 1.04 [95% CI: 1.01–1.09], P = 0.012). Here, MIF is linked to Pleural effusion.