When you have jaundice, fatigue, abdominal pain, behavioural changes, tremor, or other symptoms that your doctor thinks may be due to Wilson’s disease or, rarely, to copper deficiency or excess; at intervals when you are being treated for a copper-related condition
No test preparation is needed
This test measures the amount of copper in the blood, urine, or liver (hepatic). Copper is an essential mineral that the body incorporates into enzymes. These enzymes play a role in the regulation of iron metabolism, formation of connective tissue, energy production at the cellular level, the creation of melanin, and the function of the nervous system and brain.
Copper is found in many foods including nuts, chocolate, mushrooms, shellfish, whole grains, dried fruits, and liver. Drinking water may acquire copper as it flows through copper pipes, and food may acquire it when people cook or serve food in copper dishes. Normally, the body absorbs copper from the intestines, makes it non-toxic by binding it to a protein, and transports it to the liver. The liver stores some of the copper and binds most of the rest to a protein called apocaeruloplasmin that, when copper is attached, becomes the enzyme caeruloplasmin. About 95% of the copper in the blood is bound to caeruloplasmin. The liver excretes excess copper into the bile and it is removed from the body in the stool. Some copper is also excreted in the urine.
Both excesses and deficiencies of copper are rare. Wilson’s disease, an inherited disorder, can lead to excess storage of copper in the liver, brain, and other organs. This can cause tissue damage and signs and symptoms such as:
- nausea, abdominal pain
- behavioural changes
- ifficulty walking and/or swallowing
If the kidneys are involved, then urine production may be decreased or absent. Some of these symptoms may also be seen with copper poisoning that is due to acute or chronic environmental exposure to copper or due to conditions such as liver disease or obstructions that prevent or inhibit copper metabolism and excretion.
Copper deficiencies may occasionally occur in patients who have conditions associated with severe malabsorption, such as cystic fibrosis and coeliac disease, and in infants exclusively fed cow-milk formulas. Findings may include reduced white blood cells, osteoporosis, and microcytic anaemia. A rare X-linked genetic condition called Menkes kinky hair syndrome leads to copper deficiencies in the brain and liver of affected infants. The disease, which affects primarily males, is associated with seizures, delayed development, abnormal artery development in the brain, and unusual grey brittle kinky hair.
How is the sample collected for testing?
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
How is it used?
Copper testing is primarily used to help diagnose Wilson’s disease. If a doctor suspects Wilson’s disease, then he/she would typically use a total and/or free (unbound) blood copper test alongside the caeruloplasmin concentration. If these tests are abnormal or equivocal, then they may be followed by a 24-hour urine copper test to measure copper excretion and a hepatic (liver) copper test to evaluate copper storage. Genetic testing may also be performed to detect mutations in the ATP7B gene if Wilson’s disease is suspected. However, these tests have limited availability and are usually performed in special reference or research laboratories.
If a doctor suspects copper toxicity, copper deficiency, or a disorder that is inhibiting copper metabolism, then he/she may use blood and/or urine copper tests along with caeruloplasmin to help evaluate the patient’s condition. One or more copper tests may be requested to help monitor the effectiveness of treatment for Wilson’s disease, copper excess or copper deficiency.
When is it requested?
One or more copper tests are requested along with caeruloplasmin when someone has signs and symptoms that a doctor suspects may be due to Wilson’s disease, excess copper storage, copper poisoning, or due to a copper deficiency. These signs and symptoms may include:
- nausea, abdominal pain
- behavioural changes
- difficulty walking and/or swallowing
One or more of the copper tests may be requested periodically when monitoring is recommended.
A hepatic copper test may be requested to further investigate copper storage when copper and ceruloplasmin results are abnormal or equivocal.
What does the test result mean?
Copper test results must be evaluated in context and are usually compared to caeruloplasmin concentration. Abnormal copper results are not diagnostic of a specific condition; they indicate the need for further investigation. Interpretation can be complicated by the fact that caeruloplasmin may be elevated whenever inflammation or severe infections are present. Both caeruloplasmin and copper are also increased during pregnancy and with oestrogen and oral contraceptive use.
Test results may include:
Low blood copper concentrations along with increased urine copper excretion, low caeruloplasmin concentrations, and increased hepatic copper are typically seen with Wilson’s disease.
Increased blood and urine copper concentrations and normal or increased caeruloplasmin concentration may indicate exposure to excess copper or may be associated with conditions that decrease copper excretion – such as liver disease. Increased hepatic copper may be present with chronic conditions.
Decreased blood and urine copper concentrations and decreased caeruloplasmin may indicate a copper deficiency.
Normal hepatic copper may indicate that copper metabolism is functioning properly or that the distribution of copper in the patient’s liver is uneven and the sample is not representative of the person’s condition.
If a patient is being treated for excess copper storage with chelators, then the 24-hour urine copper concentrations may be high until body copper stores decrease. Eventually, blood copper and 24-hour urine copper concentrations should normalise.
If someone is being treated for a condition related to copper deficiency and his caeruloplasmin and total copper concentrations begin to rise, then it is likely that the condition is responding to the treatment.
Is there anything else I should know?
Medications such as oral contraceptives, carbamazepine and phenobarbital can increase blood copper concentration. They may also be elevated with rheumatoid arthritis and with some cancers, and decreased with a variety of conditions associated with malabsorption, such as cystic fibrosis.
Total serum copper concentrations are normally low at birth, rise over the next few years, peak, and then decline slightly to a relatively stable level.
Care must be taken, especially with a 24-hour urine sample, not to contaminate the sample with an external source of copper. Talk to your doctor and/or the laboratory that will perform your test about necessary precautions. If a urine or blood copper test result is higher than the doctor expects, then he may have you repeat the test to confirm the findings.
Should everyone's copper metabolism be evaluated?
General screening for copper concentrations is not recommended or necessary. Many people with conditions not associated with copper, such as people with infections or inflammation, may have temporarily increased concentrations.
Can I choose either a blood (total or free) or urine copper test?
These tests provide complementary information. It is up to you and your doctor to determine which tests are necessary to evaluate your condition.
What happens if I am exposed to toxic amounts of copper?
Copper poisoning can cause vomiting and diarrhoea and, in some cases, can lead to liver and kidney damage. You should talk to your doctor if you think that you have been exposed.
Should I be taking copper supplements or trying to get more copper in my diet?
In most cases, a regular diet satisfies the body's requirements for copper. Talk to your doctor before taking any supplements or changing your diet.