9782. Copper (urine)

Copper is an essential trace element. A urine copper test is used to assess the excretion of copper from the body, which is particularly important in the diagnosis of Wilson–Konovalov disease, where urinary copper excretion may be increased due to copper accumulation in the liver and other organs. The test may also be used to monitor treatment and assess copper exposure.

Copper exists in the human body in two oxidation states, Cu²⁺ and Cu⁺, and its ability to readily switch between these states gives it redox properties. The liver is the key organ involved in copper metabolism. More than 90% of copper is transported from the liver to peripheral tissues bound to ceruloplasmin. Copper is an essential trace element involved in iron metabolism, collagen formation, and the functioning of the immune and nervous systems, as well as in neurotransmitter synthesis and other processes.

Copper is primarily obtained from food and water. Foods rich in copper include nuts, dark chocolate, liver, cereals, and seafood. Small amounts of copper may enter drinking water from copper pipes and copper cookware.

Copper is absorbed in the intestine, binds to proteins, and is transported to the liver, where it is stored and subsequently released when needed, mainly in complex with ceruloplasmin. In blood, approximately 95% of copper is bound to ceruloplasmin and 5% to albumin. Only a small fraction is present in free form. Copper is eliminated primarily through bile, with a smaller amount excreted in urine. Under normal conditions, only a small amount of copper is present in urine.

Copper deficiency or excess is relatively uncommon but can have serious consequences.

Wilson–Konovalov disease (hepatolenticular degeneration) is an autosomal recessive genetic disorder characterized by excessive accumulation of copper in internal organs, particularly the liver and brain. One characteristic sign is the presence of Kayser–Fleischer rings around the iris, caused by copper deposits. Symptoms may include anemia, nausea, abdominal pain, jaundice, dystonia, tremor, and psychiatric disorders. A similar clinical picture may occur with acute or chronic occupational copper poisoning or environmental copper exposure.

Chronic liver diseases may be associated with impaired copper metabolism. Copper deficiency may develop in severe malabsorption, for example, in cystic fibrosis or celiac disease. Copper deficiency may manifest as microcytic anemia, osteoporosis, and neutropenia. In Menkes disease, a genetic disorder of copper metabolism, children may develop growth retardation, neurological disorders, and characteristic hair abnormalities.

Increased urinary copper levels are characteristic of Wilson–Konovalov disease and may also occur in hemochromatosis, biliary cirrhosis, thyrotoxicosis, various infections, and a number of acute, chronic, and malignant diseases, including leukemia. Urinary copper concentrations may also increase during pregnancy and in patients taking contraceptives or estrogens.

Low urinary copper levels may be observed in malnutrition, hypoproteinemia, malabsorption, and nephrotic syndrome.

Increased zinc intake can interfere with normal intestinal copper absorption, resulting in decreased blood copper levels.

• When Wilson–Konovalov disease is suspected — an inherited disorder characterized by excessive accumulation of copper in the liver, brain, and other organs, resulting in increased urinary copper excretion.
• To monitor the effectiveness of treatment for Wilson–Konovalov disease with medications that promote the elimination of copper from the body.
• When copper poisoning is suspected, although a blood copper test is more commonly used in this situation.
• In rare cases of certain liver diseases that may affect copper metabolism and excretion.
• As prescribed by a physician when symptoms suggest a disorder of copper metabolism, particularly when blood copper test results are inconclusive.

• Urine

Thorough cleaning of the external genitalia: