Wilson's disease is best diagnosed by

Answer is B (Increased urinary copper excretion): Wilson's Disease is charachterized by increased urinary copper excretion. Increased urinary copper excretion over 24 hours is an extremely useful test (+++) for diagnosis of Wilson's disease. Wilson's disease is associated with low levels of serum ceruloplasmin and high urinary copper excretion The basic defect in Wilson's disease is reduced biliary excretion of copper due to a mutation of gene on chromosome 13 which promotes copper excretion. This leads to accumulation of copper initially in the liver and subsequently in plasma and other systems once liver is saturated. Serum ceruloplasmin is the main copper binding protein in the blood and once excess copper spills into the blood, levels of free ceruloplasmin are decreased. Also excess copper is eventually excreted in urine and hence urinary copper levels are increased or high.