Management of Serum Copper 120 mcg/dL
A serum copper level of 120 mcg/dL (normal range typically 70-140 mcg/dL) requires calculation of non-ceruloplasmin bound copper and measurement of serum ceruloplasmin to determine if this represents normal copper status, Wilson's disease, or another copper metabolism disorder. 1
Immediate Diagnostic Steps
Calculate Non-Ceruloplasmin Bound (Free) Copper
Measure serum ceruloplasmin immediately to calculate free copper using the formula: Free copper (mcg/dL) = Total serum copper (mcg/dL) - [3 × ceruloplasmin (mg/dL)]. 2
Normal free copper is ≤15 mcg/dL, while levels >25 mcg/dL suggest Wilson's disease in untreated patients. 2, 1
If ceruloplasmin is extremely low (<5 mg/dL), this strongly suggests Wilson's disease despite the seemingly normal total copper. 2, 1
Obtain 24-Hour Urinary Copper Excretion
Collect 24-hour urine for copper measurement with proper technique to avoid contamination. 2, 1
Levels >100 mcg/24 hours indicate Wilson's disease, though 16-23% of Wilson's disease patients may have lower values at presentation. 2
Levels >40 mcg/24 hours (the better diagnostic threshold) warrant further investigation. 2
Clinical Context Determines Next Steps
If Evaluating for Wilson's Disease
Perform slit-lamp examination for Kayser-Fleischer rings, which strongly support the diagnosis when present. 1
Consider that total serum copper is usually decreased in Wilson's disease, not elevated, due to low ceruloplasmin. 2
Exception: In acute liver failure from Wilson's disease, serum copper may be markedly elevated (potentially to 120 mcg/dL or higher) due to sudden release from tissue stores. 2
Normal or elevated total copper with low ceruloplasmin indicates elevated free copper, suggesting Wilson's disease. 2
If Patient Has Risk Factors for Copper Deficiency
A serum copper of 120 mcg/dL is well above the deficiency threshold (<70 mcg/dL) and essentially excludes copper deficiency. 3, 4, 5
Risk factors for deficiency include: prior gastric bypass surgery, zinc overload, malabsorption syndromes, prolonged enteral nutrition, or continuous renal replacement therapy. 5, 6, 7
Copper deficiency typically presents with serum copper 3-70 mcg/dL, not 120 mcg/dL. 3, 6
If Patient Has Cholestatic Liver Disease
Chronic cholestasis can elevate non-ceruloplasmin bound copper, mimicking Wilson's disease biochemically. 2
Correlate with clinical presentation, liver function tests, and imaging to distinguish from Wilson's disease. 2
If Acute Liver Failure is Present
Elevated serum copper in acute liver failure can occur from any etiology, not just Wilson's disease. 2, 1
Calculate free copper and obtain urinary copper to help differentiate Wilson's disease from other causes. 2, 1
Common Pitfalls to Avoid
Do not rely on total serum copper alone for diagnosis—it is usually decreased in Wilson's disease despite being a copper overload disorder. 2, 1
Always measure ceruloplasmin and calculate free copper rather than interpreting total copper in isolation. 2, 1
Be aware that immunologic ceruloplasmin assays may overestimate levels, potentially giving falsely negative free copper calculations. 2
Normal ceruloplasmin does not exclude Wilson's disease—10-20% of Wilson's disease patients have normal ceruloplasmin levels. 2
If Wilson's Disease is Confirmed
Initiate chelation therapy (penicillamine or trientine) or zinc therapy based on disease severity and presentation. 1
Monitor free copper during treatment, with adequately treated patients typically having levels <10 mcg/dL. 1
Monitor 24-hour urinary copper every 6-12 months to assess treatment efficacy. 1
Continue treatment during pregnancy with close monitoring if the patient is female of childbearing age. 1