Copper is an essential element for proper cell function. It is involved in the regulation of iron metabolism, the formation of connective tissue, proper nervous system function, etc. Blood copper is transported by ceruloplasmin and stored in the liver. Excess copper is eliminated mostly through bile and a small portion in the urine. Copper deficiencies (malabsorption, cystic fibrosis, celiac disease, Menke’s disease) and excess copper (water and food contamination, industrial environment) are rare, but can lead to many health problems. Wilson’s disease is a genetic disorder accompanied by the accumulation of copper in the tissues, particularly the liver.
Plasma copper levels must be interpreted in light of levels of ceruloplasmin, the protein responsible for transporting copper throughout the body and, as appropriate, urine copper and copper in the liver. In copper poisoning, plasma and urine copper levels as well as ceruloplasmin levels are all generally high. In copper deficiency, all three levels are low. In Wilson’s disease, plasma copper and ceruloplasmin are low to low-normal, while urine copper is very high.