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Caeruloplasmin

This test measures the amount of caeruloplasmin in the blood. Caeruloplasmin is a copper-containing enzyme that plays a role in the body's iron metabolism. Copper is an essential mineral that is absorbed into the body through diet. It is absorbed in the intestines and then transported to the liver where it is stored or used in the production of a variety of enzymes. The liver binds copper to apocaeruloplasmin to produce caeruloplasmin and then releases it into the bloodstream. About 95 per cent of the copper in the blood is bound to caeruloplasmin.

Caeruloplasmin is primarily ordered along with blood and/or urine copper tests to help diagnose Wilson disease, an inherited disorder associated with decreased levels of caeruloplasmin and excess storage of copper in the liver, brain, and other organs. Rarely, it may be ordered to help diagnose or differentiate between conditions associated with copper deficiencies.

It is ordered along with copper tests when someone has signs and symptoms that may be due to Wilson's disease such as:

  • anaemia
  • nausea, abdominal pain
  • jaundice
  • fatigue
  • behavioural changes
  • tremors
  • difficulty walking and/or swallowing
  • dystonia

Rarely, caeruloplasmin is ordered along with copper tests when a copper deficiency is suspected and when monitoring is required.

Caeruloplasmin levels alone are not diagnostic of a specific condition and are usually evaluated along with copper levels.

Test results may include:

  • Decreased levels of caeruloplasmin and blood copper concentrations together with increased urine copper levels suggest Wilson disease.
  • About 5 per cent of people with Wilson disease who have neurological symptoms will have normal caeruloplasmin levels as will up to 40 per cent of those with hepatic symptoms, especially if they have recently become ill.
  • Low caeruloplasmin and urine and/or blood copper concentrations suggest copper deficiency.
  • Anything that interferes with the supply of copper or with the body's ability to metabolise copper has the potential to affect blood caeruloplasmin and copper concentrations.

Caeruloplasmin may be increased in a variety of circumstances where the test is not used as a clinical tool. These may include:

  • Caeruloplasmin is an acute phase reactant. It is frequently elevated when someone has inflammation, severe infection or tissue damage and it may be increased with some cancers.
  • It may be increased during pregnancy and with the use of oestrogen and oral contraceptive pills.

  • Should everyone have a caeruloplasmin test?

Caeruloplasmin is not a routine test. Unless your doctor suspects that you have Wilson disease or a problems with your copper metabolism, it is unlikely that you will ever have this test performed.

  • Can I have the caeruloplasmin test done in my doctor's office?

No. It is a specialised test that is not offered in every laboratory. Your blood sample may need to be sent to a reference laboratory.

  • Do I need to have a liver biopsy?

If Wilson disease is strongly suspected based upon blood, urine and imaging test results, a liver biopsy may be performed to evaluate hepatic (liver) copper content and the extent of liver damage.