Copper
Also known as: Cu, Serum Copper
What Does Copper Measure?
Copper (Cu) is an essential trace mineral measured in the blood, typically as serum or plasma copper. This test quantifies the amount of copper circulating in your bloodstream, most of which (about 90-95%) is bound to a protein called ceruloplasmin, with the remainder loosely bound to albumin or free. The test reflects both dietary copper intake and the body's ability to absorb, transport, and utilize this mineral.
Why Does Copper Matter?
Copper plays a critical role in numerous biological processes, including the formation of red blood cells, maintenance of nerve cells, immune function, collagen synthesis, and energy production. It acts as a cofactor for several important enzymes, such as superoxide dismutase (an antioxidant enzyme) and cytochrome c oxidase (involved in cellular energy). Abnormal copper levels can signal genetic disorders like Wilson's disease or Menkes disease, nutritional deficiencies, liver disease, or inflammatory conditions. Monitoring copper is also important in clinical nutrition, particularly in patients receiving long-term intravenous nutrition or those with malabsorption syndromes.
Normal Ranges
Males
70-140 mcg/dL (11-22 µmol/L)
Females
80-155 mcg/dL (13-24 µmol/L) — slightly higher; pregnancy can elevate levels further
Children
Varies by age; newborns: 20-70 mcg/dL; older children: 80-190 mcg/dL
Causes of High Levels
- Wilson's disease (copper accumulation disorder causing elevated serum copper in some presentations)
- Liver disease (cirrhosis, hepatitis) impairing copper metabolism
- Pregnancy or estrogen/oral contraceptive use stimulating ceruloplasmin production
- Chronic inflammatory conditions (copper is an acute-phase reactant that rises with inflammation)
- Rheumatoid arthritis and other autoimmune diseases
- Certain cancers, including lymphoma and leukemia
Causes of Low Levels
- Dietary copper deficiency from inadequate intake or prolonged total parenteral nutrition
- Menkes disease, a rare genetic disorder impairing copper absorption and transport
- Excessive zinc supplementation (zinc competes with and blocks copper absorption)
How to Improve Your Copper
Diet
- Eat copper-rich foods such as beef liver, oysters, and shellfish (3 oz of beef liver provides ~12 mg copper)
- Include nuts and seeds, especially cashews, sunflower seeds, and sesame seeds (tahini)
- Consume legumes like lentils, chickpeas, and black beans regularly
- Add dark chocolate (70%+ cacao) and cocoa powder as copper-containing treats
- Incorporate whole grains such as barley, quinoa, and oats to boost daily copper intake
Supplements
- Copper gluconate or copper glycinate: 1-2 mg/day is a typical supplemental dose for deficiency (do not exceed 10 mg/day)
- Ensure zinc-to-copper ratio is balanced; if taking zinc supplements (>25 mg/day), add 2 mg copper to prevent depletion
- Avoid self-supplementing copper without medical guidance, as excess is toxic; always confirm deficiency via lab testing first
- Multivitamins typically contain 0.9-2 mg copper, which may be sufficient for mild insufficiency
- Copper citrate is another well-absorbed supplemental form suitable for those with digestive sensitivity
Related Biomarkers
Frequently Asked Questions
What is the difference between serum copper and ceruloplasmin tests?
Serum copper measures the total amount of copper in your blood, while ceruloplasmin measures the specific copper-carrying protein. Since about 90-95% of blood copper is bound to ceruloplasmin, the two tests are closely related. However, in Wilson's disease, total serum copper can be elevated while ceruloplasmin is paradoxically low, because free (unbound) copper accumulates in the blood. Doctors often order both tests together for a more complete picture.
Can high copper levels be dangerous?
Yes, excessive copper in the body — whether from genetic causes like Wilson's disease, environmental exposure, or over-supplementation — can be harmful. High free copper is toxic to cells and can damage the liver, brain, kidneys, and eyes. Wilson's disease, if untreated, can lead to liver failure and neurological damage. Copper toxicity from supplements or contaminated water is less common but can cause nausea, vomiting, liver damage, and in severe cases, kidney failure.
Why is my copper level high during pregnancy?
Copper levels naturally rise during pregnancy, often reaching up to twice the normal level by the third trimester. This is because estrogen stimulates the liver to produce more ceruloplasmin (the copper-carrying protein), which increases total serum copper. This elevation is considered physiological and normal during pregnancy and typically returns to baseline after delivery. Elevated copper in pregnancy does not usually require treatment.
Can low copper cause anemia?
Yes. Copper deficiency can mimic iron-deficiency anemia and can be misdiagnosed if copper levels are not tested. Copper is essential for iron metabolism — it helps with iron absorption from the gut and is needed to incorporate iron into red blood cells. When copper is low, iron accumulates in tissues but cannot be effectively used, leading to anemia that does not respond to iron supplementation. This is called copper deficiency anemia, and it is corrected by addressing the copper deficit.