Abnormalities of chemical tests for copper metabolism in chronic active liver disease: differentiation from Wilson's disease.

Because identical clinical findings, alterations of hepatic function, and changes in hepatic morphology can occur in Wilson's disease (WD) and chronic active liver disease (CALD), chemical tests that reflect copper metabolism are important in the differential diagnosis of these conditions. The authors therefore measured 24-hr urinary copper excretion, hepatic copper concentration, and serum ceruloplasmin concentration in 54 patients with CALD. Twenty-four hour urinary copper excretion was increased in about 50% of patients, was significantly higher during active disease compared to remission, and was in the WD range in approximately 10% of patients. Hepatic copper concentration was also increased in the majority of patients, generally during active disease, and it sometimes overlapped with values reported in WD. By contrast, serum ceruloplasmin levels were elevated in nearly one-half the Cald patients and were never below normal. It is concluded that the chemical tests routinely used to assess copper metabolism in WD are frequently abnormal in CALD. Because the serum ceruloplasmin concentration never fell in the WD range and often was elevated, it is the most reliable routine chemical screening test to differentiate between CALD and WD.