Diagnosis of Wilson disease (WD) can be difficult because of its protean clinical presentation, but early diagnosis is important because effective treatment is available and can prevent disease progression. Using quantitative proteomics, we characterized proteins that are differentially expressed in WD compared to normal liver. Further the expression of MT1M and COX17 were validated using immunohistochemistry. We found diffuse MT immunoreactivity in all liver specimens from patients with WD (n=20), the intensity of the staining was moderate to strong. This staining pattern was distinct from that seen in specimens from the control groups which included diseases that may be in the clinical or histologic differential of WD (steatohepatitis (n=51), chronic viral hepatitis (n=40), autoimmune hepatitis (n=50), chronic biliary tract disease (n=42), and normal liver (n=20)). COX17 immunostain showed no significant difference in expression between the WD and control groups. MT had higher sensitivity than rhodanine for diagnosis of WD. While the quantitative liver copper assays also had high sensitivity, they require more tissue, have a higher cost, have longer turnaround time, and are less widely available than an immunohistochemical stain. We conclude that MT IHC is a sensitive immunohistochemical stain for the diagnosis of Wilson disease that could be widely deployed as a screening tool for liver biopsies in which Wilson disease is in the clinical or histologic differential diagnosis.