Copper blood test: what the result means (Cu)

Copper is an essential trace element that almost all of the body's tissues need in small amounts — the body cannot make it itself, so it has to get it from food (for example from oysters and other seafood, wholegrain products, beans, nuts, potatoes and organ meats). Copper helps the body make red blood cells together with iron, takes part in forming blood vessels, supports the nervous system, the immune system and the bones, and helps iron to be absorbed. Most of the copper in the blood is bound to the protein ceruloplasmin, which is why a copper test is often assessed together with a ceruloplasmin test. Too much copper in the body is toxic — in the inherited Wilson's disease, for example, copper builds up in the liver, the brain and other organs. Too little copper occurs less often and is most often associated with poor absorption or an inadequate diet.

• When Wilson's disease is suspected — when there is a family history, or symptoms such as abdominal pain, signs of jaundice, tremor, or difficulty speaking or swallowing that appeared between roughly the ages of 4 and 40
• When ceruloplasmin is tested at the same time, in order to assess copper metabolism
• In infants, when Menkes syndrome is suspected — a rare inherited disorder of copper absorption
• When there are signs of possible copper deficiency — an unusually low white blood cell count, thinning of the bones, tiredness, tingling in the limbs, pale skin
• When copper poisoning is suspected (for example from environmental or household sources) — when there is abdominal pain, diarrhoea, vomiting or signs of jaundice
• To monitor treatment when a disorder of copper metabolism is already known

We do not currently have a checked numeric reference range from a reliable primary source, so we do not give one here. You will find your own laboratory's exact reference interval on your result sheet — it can differ depending on the laboratory and the method used.

A raised copper level

A raised copper level in the blood is most often associated with inflammation or infection (copper in the blood rises together with ceruloplasmin, which is an acute-phase protein), and also with pregnancy, the use of oral contraceptives or oestrogens, and some chronic diseases. Less often the cause is copper poisoning from environmental sources.

What can raise copper

• Inflammation, infection or tissue damage — ceruloplasmin (and copper along with it) rises as an acute-phase protein
• Pregnancy, the use of oral contraceptives or oestrogen therapy
• Chronic diseases — heart disease, rheumatoid arthritis, leukaemia, Hodgkin lymphoma
• Copper poisoning — for example from old coins, certain insecticides or copper-contaminated sources

Symptoms that can accompany a raised copper level

• Abdominal pain, nausea, vomiting
• Signs of jaundice — yellowed skin and whites of the eyes, darker urine, paler stools
• Tremor, muscle stiffness, difficulty speaking or swallowing
• Itchy skin, swelling
• Characteristic brownish or greenish rings in the cornea of the eye (in Wilson's disease)

• A ceruloplasmin test — assessed together with copper, especially when Wilson's disease is suspected
• Liver markers and the amount of copper in the urine — they help to refine the diagnosis
• Whether there is any inflammation or infection at the time that could temporarily raise the result
• Any medicines or supplements being taken (those containing oestrogen, for example) that could affect the result

A low copper level

A low copper level in the blood occurs less often than a raised one and is most often associated with poor copper absorption, an inadequate diet, taking too much zinc, or rare inherited disorders such as Menkes syndrome in infants. Low copper together with low ceruloplasmin is also characteristic of Wilson's disease, so a doctor investigates that combination further.

What can lower copper

• Wilson's disease — although copper builds up in the liver and other organs, the total amount of copper in the blood is most often reduced because ceruloplasmin is low
• An inadequate diet or poor absorption of nutrients (including coeliac disease and other malabsorption conditions)
• Taking too much zinc in supplements — zinc reduces copper absorption
• Menkes syndrome — a rare inherited disorder of copper absorption in infants
• Severe liver or kidney disease

Signs that can accompany a low copper level

• An unusually low white blood cell count
• Thinning of the bones (osteoporosis)
• Tiredness, weakness
• A tingling sensation in the limbs
• Pale skin
• Anaemia

What is usually assessed alongside a low result

• A ceruloplasmin test and a full blood count — to assess whether there is anaemia
• Diet and any conditions that can interfere with absorption
• The use of zinc supplements or other medicines
• In infants — assessment for signs of Menkes syndrome