Which laboratory tests are essential for the diagnosis of Wilson's Disease, and what are their expected findings?

Essential laboratory tests for diagnosing Wilson's disease include serum ceruloplasmin, 24-hour urinary copper excretion, and hepatic copper quantification via liver biopsy. Serum ceruloplasmin is typically low in Wilson's disease, often below 0.2 g/L, reflecting impaired copper transport NICE NG50 Langner & Denk 2004. However, ceruloplasmin can be normal in some cases, especially in acute liver failure or inflammatory states, so it is not solely diagnostic NICE NG50 Aggarwal & Bhatt 2013. 24-hour urinary copper excretion is elevated, usually exceeding 100 µg/24h, indicating increased free copper excretion due to defective biliary copper excretion NICE NG50 Chanpong & Dhawan 2022. Liver biopsy with quantitative copper measurement remains the gold standard, showing hepatic copper concentrations greater than 250 µg/g dry weight, confirming copper accumulation NICE NG50 Langner & Denk 2004. Additional supportive tests include slit-lamp examination for Kayser-Fleischer rings and genetic testing for ATP7B mutations, but these are adjuncts rather than primary laboratory diagnostics NICE NG50 Aggarwal & Bhatt 2013. Serum free copper (non-ceruloplasmin-bound copper) is often elevated but less commonly used in routine diagnosis due to variability Chanpong & Dhawan 2022. Thus, the diagnostic approach integrates low ceruloplasmin, elevated urinary copper, and hepatic copper quantification to establish Wilson's disease.