Serum Copper
Serum copper is mostly bound to ceruloplasmin, with a small 'free' fraction. Serum copper testing is mainly used alongside ceruloplasmin in evaluating Wilson's disease (copper overload, low ceruloplasmin) and Menkes disease (copper deficiency in infants). Because most blood copper is ceruloplasmin-bound, serum copper often tracks ceruloplasmin — the more informative measure in Wilson's is actually calculated free copper and 24-hour urinary copper excretion.
Reference Ranges
Male
70 – 140
µg/dL
Female
80 – 155
µg/dL
Child
80 – 190
µg/dL
Higher in children and pregnancy
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low serum copper with low ceruloplasmin is typical of Wilson's disease but also occurs with malnutrition, prolonged parenteral nutrition without trace element supplementation, zinc excess (zinc and copper compete for absorption), malabsorption, and the rare Menkes disease in infants. Copper deficiency can cause anemia, neutropenia, and myelopathy (spastic gait, sensory loss).
What High Levels Mean
Elevated serum copper with high ceruloplasmin is usually an acute-phase response or estrogen-related (oral contraceptives, pregnancy) — both raise ceruloplasmin. Elevated serum copper with low or normal ceruloplasmin, especially with high free copper and high urinary copper, suggests Wilson's disease. Acute copper poisoning is rare but can occur from contaminated water or occupational exposure.
Frequently Asked Questions
What is free copper and why is it important?
Free copper is the fraction not bound to ceruloplasmin. It is calculated as: total serum copper − (ceruloplasmin × 3). In Wilson's disease, free copper is elevated (>25 µg/dL) even though total serum copper and ceruloplasmin may be low. Elevated free copper drives tissue deposition in the liver, brain, and eye — the actual cause of Wilson's pathology.
Can zinc supplements cause copper deficiency?
Yes. Chronic high-dose zinc supplementation (>50 mg/day for extended periods) can induce copper deficiency by competing for absorption at the same intestinal transporter. Symptoms include anemia, neutropenia, and rarely a myelopathy resembling B12 deficiency. Long-term zinc users should have copper checked periodically, especially if taking zinc for longer than a few months.
Does serum copper need fasting?
Ideally yes — though not strictly required. Serum copper can vary mildly with meals and diurnal rhythms. For Wilson's workup, morning fasting samples are preferred to minimize variability. Hemolyzed samples falsely elevate copper and should be redrawn. Always check with the specific lab's collection instructions.
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mg/dLThis information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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