Question

In Wilson disease, the best choice of investigation is:

• A. Serum copper
• B. Ceruloplasmin
• C. Hepatic copper estimation
• D. Urine copper

Hint:

The hepatocyte cannot load copper onto its carrier protein — so that carrier protein is low in the blood and is the easy first test.

Answer 1

The Correct Option is B

Step 1: Recall the disease. Wilson disease (hepatolenticular degeneration) is an autosomal-recessive defect of the ATP7B copper-transporting ATPase. The hepatocyte cannot incorporate copper into ceruloplasmin nor excrete copper into bile, so copper accumulates in the liver, brain (basal ganglia), cornea (Kayser-Fleischer rings) and other organs.

Step 2: Link the defect to the screening test. Because copper cannot be loaded onto apoceruloplasmin, the circulating ceruloplasmin level is characteristically LOW. A reduced serum ceruloplasmin is the standard, widely available first-line/screening biochemical investigation for Wilson disease (typically <20 mg/dL).

Step 3: Confirm the correct option. Among the listed choices, ceruloplasmin is the best routine investigation, so option B is correct. (It is best combined with a 24-hour urinary copper and slit-lamp exam for KF rings; liver biopsy copper is the gold standard for confirmation but is invasive.)

Step 4: Exclude the distractors. Serum (total) copper is often low or normal and is unreliable because most circulating copper is ceruloplasmin-bound, while it is the FREE copper that rises - so A is not the best single test. Hepatic (liver biopsy) copper estimation is the confirmatory gold standard but is invasive and not the practical 'best choice' screening investigation; C is not the intended answer. 24-hour urinary copper is elevated and useful (especially for diagnosis and monitoring) but is a supportive test rather than the single best routine investigation here; D is not the best.

Final answer: Option B - Ceruloplasmin.