When you have symptoms that your doctor thinks are suggestive of Wilson disease or copper deficiency, or results from other blood tests suggest Wilson disease or copper deficiency is possible. It can also be tested at intervals when monitoring a copper related disease or its treatment.
A blood sample taken from a vein in your arm
No test preparation is needed
This test measures the amount of caeruloplasmin in the blood, and is often requested alongside other tests, such as copper levels. Caeruloplasmin is a copper-containing enzyme that plays a role in iron metabolism and copper transport around the body. Copper is an essential mineral that is absorbed in the intestines and then carried to the liver, where it is stored or used to make a variety of other enzymes. The liver binds copper to apocaeruloplasmin to produce caeruloplasmin which is then released into the bloodstream. About 95% of the copper in the blood is bound to caeruloplasmin.
The caeruloplasmin blood test is not diagnostic on its own, but it provides information to your doctor as to whether copper deficiency/Wilson disease is the cause of your symptoms. Your health care team may then follow up with further testing and treatment.
How is it used?
Caeruloplasmin is primarily measured with blood and/or urine copper to help diagnose Wilson disease, a rare inherited disease associated with low levels of caeruloplasmin and excess storage of copper in the liver, brain, and other organs. Rarely, it may be used to help diagnose a disorder of copper deficiency.
When is it requested?
- tummy pain
- behavioural changes
- difficulty walking and/or swallowing
Rarely, caeruloplasmin may also be requested with serum copper when your doctor suspects that you have a copper deficiency and periodically if monitoring is recommended.
What does the test result mean?
- Low caeruloplasmin is seen in up to 90% of patients with Wilson disease, and would also be expected in cases of copper deficiency.
- However, low caeruloplasmin levels can sometimes be seen in patients who do not have Wilson disease or copper deficiency, so this alone cannot diagnose a copper related disease and needs to be interpreted with results of other tests such as urine/blood copper, clinical findings, or liver biopsy results
- A normal caeruloplasmin level does not definitively exclude Wilson disease as a small number of patients may have normal caeruloplasmin levels.
- Acute liver disease or high levels of oestrogen (e.g. contraceptive pill, hormone therapy or pregnancy) can also transiently increase low caeruloplasmin levels into the normal range.
Is there anything else I should know?
Caeruloplasmin may be increased in a variety of circumstances which need to be considered when using it to diagnose or monitor Wilson disease or copper deficiency. These circumstances may include:
- Caeruloplasmin levels increases when someone has inflammation, severe infection, tissue damage, and some cancers.
- Increases are also seen during pregnancy and with the use of oestrogen, oral contraceptives, and medications such as carbamazepine, phenobarbital, and valproic acid.
Do I need to have a liver biopsy?