What is copper?
Copper is a trace element: you need little of it, but without it things go wrong. It sits in a handful of enzymes with big jobs. One makes iron usable, so that it ends up in your red blood cells; without copper an anaemia develops that looks like iron deficiency but does not respond to iron. One makes collagen and elastin firm, in your blood vessels, your bones and your skin. One clears free radicals, and one protects the insulation around your nerves. Copper is in shellfish, nuts, seeds, whole grains, cocoa and liver. Most of the copper in your blood, roughly nine parts in ten, is bound to ceruloplasmin, a protein your liver makes. That makes the copper value a double measurement: it says something about your copper and something about that protein. Ceruloplasmin rises with inflammation, in pregnancy and with oestrogen, so with the pill too, and then lifts the copper with it without you having more copper. The other way round, a low copper with a low ceruloplasmin is the trail to Wilson's disease, in which copper actually accumulates in liver and brain. Your report shows copper in µmol/L. Normal is about 12 to 20.1 µmol/L where the labs overlap. It is drawn in a special tube, because ordinary tubes can shed traces of metal.
Why is copper relevant?
The reason copper is interesting for anyone who wants to stay healthy lies in zinc. Zinc and copper compete for the same uptake in the gut, and plenty of zinc sets the gut cells to holding on to copper and disposing of it. Anyone who takes a high dose of zinc for months, against colds, for the skin or for testosterone, can develop a copper deficiency that way without ever thinking of it. That starts with tiredness and an anaemia that does not respond to iron, and can grow into numbness in the feet and an unsteady feeling when walking that looks like a B12 deficiency. A copper value beside a zinc value shows whether the supplement has gone too far. The second group is everyone in whom the uptake falters: after stomach surgery, with coeliac disease or a chronic gut inflammation, and in anyone who eats one-sidedly for a long time. Here too anaemia and nerve symptoms are the first signs, and here too it is reversible as soon as you see it. The third reason is rare but too important to miss: Wilson's disease, an inherited condition in which the liver cannot get rid of copper and it accumulates in liver and brain. That gives a low copper value and a low ceruloplasmin, often in a young adult with unexplained liver values, tremor or mood symptoms. Untreated it is serious, treated it is very manageable, and it starts with these two values side by side.
Copper reference ranges
What counts beside the number:
- Ceruloplasmin from the same draw, because most copper travels on it
- Zinc, and above all whether you take it as a supplement and how much
- CRP, because an inflammation lifts ceruloplasmin and copper together
- The pill, hormone therapy or a pregnancy
- Your blood count and ferritin, because a copper deficiency gives an anaemia that does not respond to iron
- Stomach surgery or gut disease, and in a young person with liver values, Wilson's disease
The band above is where the labs overlap; for copper the ranges sit close together. Women on the pill or pregnant sit higher, because oestrogen raises the protein copper travels on; that is as it should be. A baby has much lower values in the first six months. There is no national normal value for copper. Always read copper beside ceruloplasmin.
What Dutch labs actually use
12 – 20.1µmol/L
Between 9.58 and 12 and between 20.10 and 24 it depends on the lab, because each sets its limits on its own method and population. Above 24 every lab calls it abnormal.
every lab calls 12 – 20.1 µmol/L normal. Between 9.58 and 12 and between 20.10 and 24 it depends on the lab.
Every age, per lab
| Laboratory | Group | Reference range |
|---|---|---|
| Unilabs(Saltro, Medlon, SHO, Atalmedial)2026 | All ages | 10–24 µmol/L |
| Star-shl2026 | All ages | 9.58–20.10 µmol/L |
| Certe2026 | Up to 26 weeks | 4–8 µmol/L |
| From 26 weeks | 12–22 µmol/L |
Each band as the lab publishes it, retrieved in 2026, unless marked otherwise.
Copper high or low: what it means
A high copper is usually the transport protein and not the copper itself. In order of how often it occurs: an inflammation, because ceruloplasmin is an acute-phase protein; the pill or other oestrogens; a pregnancy; and rarely a liver disease in which bile does not drain properly. A high copper with a high ceruloplasmin and a high CRP is therefore an inflammation, not a copper matter. Too much copper from food or water hardly ever occurs. A low copper means too little supply, a faltering uptake, too much zinc, or a low ceruloplasmin. In order: a low ceruloplasmin, which pulls the copper down with it; plenty of zinc as a supplement; stomach surgery or gut disease; and rarely Wilson's disease. A low copper with a low ceruloplasmin in a young person with liver values or neurological symptoms is the combination you do not want to miss. What you do about it: if you take zinc, keep it to an ordinary dose and not high for months, and have copper measured alongside if you use it for longer. With a deficiency from the diet, shellfish, nuts, seeds, whole grains and cocoa usually suffice; after stomach surgery or with a gut disease copper belongs in the supplement. Count on a few months before the anaemia recovers. Always read copper beside ceruloplasmin, and beyond that beside zinc, CRP, ferritin and your blood count, and keep to one and the same lab when comparing over time.
What lowers it
Too little supply or uptake, too much zinc, or the protein copper travels on.
| Cause | How often |
|---|---|
| Low ceruloplasminThe protein most copper travels on; if that is low, from a liver problem, protein loss or an inherited cause, the copper falls with it | Often |
| Plenty of zincZinc sets the gut cells to holding on to copper and disposing of it; months of a high dose as a supplement cause a deficiency | Sometimes |
| Stomach surgery or gut diseaseCopper is absorbed in the stomach and the start of the small intestine; after a gastric bypass or with coeliac disease that falters | Sometimes |
| Wilson's diseaseAn inherited storage disease in which the liver cannot get rid of copper; low copper and low ceruloplasmin in the blood, while it accumulates in liver and brain | Rare |
What raises it
Usually the transport protein going up, not the copper itself.
| Cause | How often |
|---|---|
| InflammationCeruloplasmin is an acute-phase protein and rises with every inflammation; the copper rises with it, and CRP shows whether that is at play | Often |
| The pillOestrogen makes the liver produce more ceruloplasmin; a pregnancy and hormone therapy do that too | Sometimes |
| PregnancyCeruloplasmin rises over the course of the pregnancy and the copper with it; that is as it should be | Sometimes |
| Liver diseaseIf bile does not drain properly, the liver gets rid of copper less well and the value rises | Rare |
How does a copper blood test work?
- Referral
- Not needed. You can have copper measured yourself, preferably together with ceruloplasmin and zinc.
- Fasting
- Not needed, but skip a zinc or multimineral supplement on the day of the draw.
- The draw
- One tube of blood from a vein in your arm, in a special tube free of metal traces; that is not available at every location.
- The result
- A single number in µmol/L, which can take one to two weeks because the lab does not run the test daily.
- Where to draw
- You can draw at 250+ locations near you, no referral needed. See the locations
Frequently asked questions
What is copper?
A trace element you need in small amounts for a handful of enzymes: they make iron usable for your red blood cells, keep collagen and elastin firm, clear free radicals and protect the insulation around your nerves. It is in shellfish, nuts, seeds, whole grains, cocoa and liver. Most of the copper in your blood travels bound to ceruloplasmin, a protein from your liver.
What is a normal copper level?
About 12 to 20.1 µmol/L where the labs overlap. Women on the pill or pregnant sit higher, because oestrogen raises the protein copper travels on. Always read the value beside ceruloplasmin, because otherwise you do not know whether an abnormality is about the copper or about the protein.
What does a high copper level mean?
Usually that ceruloplasmin sits high, and not that you have too much copper. That protein rises with every inflammation, with the pill and other oestrogens and in pregnancy, and lifts the copper with it. A high copper beside a high CRP is therefore an inflammation. Rarely a liver disease in which bile does not drain properly lies behind it. Too much copper from food or water hardly ever occurs.
What does a low copper level mean?
Too little supply or uptake, too much zinc, or a low ceruloplasmin that pulls the copper down with it. Plenty of zinc as a supplement is the reason most often overlooked, and after stomach surgery or with coeliac disease the uptake falters. A copper deficiency gives tiredness, an anaemia that does not respond to iron and in time nerve symptoms. Low copper with low ceruloplasmin in a young person with liver values or neurological symptoms is the trail to Wilson's disease.
Why do you read copper together with ceruloplasmin?
Because roughly nine parts in ten of the copper in your blood are bound to that protein. If ceruloplasmin rises or falls, the copper moves with it without your copper status changing. High copper with high ceruloplasmin is the protein, usually an inflammation or oestrogen. Low copper with low ceruloplasmin is a real deficiency or, in a young person, Wilson's disease. Low copper with a normal ceruloplasmin is rare and points at the measurement.
Can zinc cause a copper deficiency?
Yes, and that is the most common way to develop one. Zinc and copper compete for uptake in the gut, and plenty of zinc sets the gut cells to holding on to copper and disposing of it. Anyone who takes a high dose of zinc for months, against colds, for the skin or for testosterone, can develop a copper deficiency that way with anaemia and numbness in the feet. Keep zinc to an ordinary dose, and have copper measured alongside if you use it for longer.
What is Wilson's disease?
An inherited condition in which the liver cannot get rid of copper into the bile, so it accumulates in liver and brain. In the blood that gives a low copper and a low ceruloplasmin, often in someone between ten and forty years old with unexplained liver values, tremor, clumsiness or mood symptoms. Untreated it is serious, treated with medicines that remove copper it is very manageable. It starts with these two values side by side.
Do I need to fast for a copper test?
No, but skip a zinc or multimineral supplement on the day of the draw. The draw goes into a special tube free of metal traces, and the result can take one to two weeks because the lab does not run the test daily.
Which tests include copper?
Copper is part of Advanced, the broader panel. It is not orderable yet.
Related biomarkers
Read on
Sources
- 1.Unilabs, test catalogue (Dutch): copper. 2026. bepalingenklapper.nl
- 2.Star-shl, test catalogue (Dutch): copper. 2026. star-shl.nl
- 3.Certe, test catalogue (Dutch): copper. 2026. bepalingenwijzer.certe.nl
- 4.Clinical Diagnostics, lab guide (Dutch): copper. 2026. clinicaldiagnostics.nl
- 5.LESA Laboratory diagnostics (Dutch primary-care laboratory agreement). 2026. richtlijnen.nhg.org
Educational information only, not medical advice. Consult a healthcare professional for clinical decisions.
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Copper is part of Advanced, the broader panel. It is not orderable yet.
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