Copper
Copper is a mineral your body needs in small amounts to use iron, build strong tissues, make energy and keep the nerves healthy. A blood copper test is mostly used to look into rare problems with how the body handles copper, so the result is never read on its own — your GP weighs it up with other tests and how you are feeling.
Targeted TestingWhat is copper?
Copper is an essential mineral that the body incorporates into enzymes. These enzymes play a role in the regulation of iron metabolism, the formation of connective tissue (the structural scaffolding of your body), energy production at the cellular level, the production of melanin (the pigment that gives skin its colour), and the function of the nervous system and brain. Most of the copper in your blood is bound to a protein called caeruloplasmin (pronounced "seer-ulo-plas-min") — in fact, about 95 per cent of blood copper travels this way. This matters for interpreting results, because caeruloplasmin is an acute-phase reactant: it rises when the body is dealing with inflammation, severe infection, or tissue damage. So a high blood copper reading can sometimes reflect inflammation rather than a true excess of copper.
Why is it tested?
Copper testing is used mainly to help investigate two specific situations. The first is Wilson disease — a rare inherited condition where the body cannot clear copper properly, leading to excess copper storing up in the liver, brain and other organs. A person with Wilson disease typically has low or normal blood copper despite copper building up in their tissues, because less copper is carried on caeruloplasmin in the bloodstream. If Wilson disease is suspected, copper is measured alongside caeruloplasmin and a urine copper test. The second situation is copper deficiency. This can happen in people with conditions that seriously block absorption — such as cystic fibrosis and coeliac disease — and in infants fed only on cow-milk formulas. When copper runs short, it can show up in a few ways. It can lower neutrophils, the immune cells that fight bacteria (a state called neutropenia). It can thin the bones (osteoporosis). And it can cause a type of anaemia with small red blood cells (microcytic anaemia) that looks like iron-deficiency anaemia but does not improve with iron.
Reference range (Australia)
Reference intervals for blood copper can differ between laboratories and may vary by sex, since caeruloplasmin (which carries most of the copper) is influenced by oestrogen. Always use the interval on your own report, which your laboratory has set for the method they use.
Reference intervals vary between laboratories. Always use the range printed on your own report.
What your result means
A lower-than-range copper level suggests possible deficiency. This is uncommon in people eating a varied diet but can occur with severe malabsorption or after certain gut surgeries. Deficiency can affect blood formation (causing a microcytic anaemia that will not respond to iron), immune cells (neutropenia), and bone strength (osteoporosis). Your GP will look at your symptoms, your diet, your iron studies and your caeruloplasmin to work out the cause.
A copper result within range is generally reassuring. Because most blood copper is caeruloplasmin-bound, your GP may look at caeruloplasmin alongside it to get the full picture, particularly if there is any concern about copper handling or inflammation.
A higher-than-range copper level is often driven by a rise in caeruloplasmin, the protein that carries most of the copper in your blood. Caeruloplasmin is an acute-phase reactant — it rises with inflammation, infection or tissue damage — so a mildly elevated copper result can simply reflect that your body was fighting something at the time. True copper excess is uncommon. High blood copper with low caeruloplasmin can be a sign of Wilson disease (where copper leaks out of the liver). Your GP will read the result alongside caeruloplasmin, liver tests and the clinical picture.
What can affect your result
Inflammation is the biggest driver of a falsely raised copper reading. Caeruloplasmin — the protein that carries about 95 per cent of blood copper — is an acute-phase reactant. It rises frequently when someone has inflammation, severe infection or tissue damage. So if you were unwell at the time of your blood test, a higher copper reading may reflect that rather than a true excess. Medications can also shift the result. Oestrogens, oral contraceptive pills, carbamazepine (an anticonvulsant), and phenobarbital (another anticonvulsant) can all increase blood copper levels, likely because they raise caeruloplasmin. On the low side, severe malabsorption — from conditions like cystic fibrosis, coeliac disease, or certain gut surgeries — can deplete copper over time. High-dose zinc supplements taken over a long period can also interfere with copper absorption.
When to act
Copper results are rarely acted on in isolation. If your result is outside the range on your report, your GP will look at it alongside caeruloplasmin, your iron studies and liver tests, your medication list, and any symptoms you have. A mildly elevated result in someone who was recently unwell may simply be an inflammatory response and not need further action. A low result in someone with unexplained anaemia or neurological symptoms is more likely to prompt further investigation. Your GP is the right person to put the number in context and decide whether anything further is needed. This page is general information and is not a substitute for advice from your GP.
Frequently asked questions
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