For example, a real-world prospective cohort study involving 2,867 patients with liver disease in secondary care showed that 17 (0.59%) patients had a serum ceruloplasmin level of < 0.2 g/L and only one out of these patients was diagnosed with WD after a comprehensive investigation [43], indicating that the ceruloplasmin had a positive predictive value of only 6% in patients with liver disease. Here, CP is linked to Wilson disease.