When the individual protein served as a candidate biomarker, the AUCs of SAA, PROZ, and C4BPB were 0.843, 0.852, and 0.860, respectively, to discriminate between patients with TB and healthy controls; 0.852, 0.796, and 0.787 to discriminate between patients with TB and those with pneumonia, or 0.693, 0.884, and 0.662 for those with COPD; and 0.601, 0.867, and 0.654, respectively, to discriminate between patients with active TB and treated TB cases. The gene discussed is C4BPB; the disease is chronic obstructive pulmonary disease.