Caeruloplasmin Blood Test: Normal Ranges, Causes & What Your Results Mean

What Is Caeruloplasmin?

Caeruloplasmin (also spelled ceruloplasmin) is a copper-carrying protein produced by the liver. It is the major copper-binding protein in the blood, carrying approximately 65–90% of the total copper circulating in your bloodstream. Each molecule of caeruloplasmin binds six copper atoms, and these copper atoms are essential for the protein's enzymatic activity.

Caeruloplasmin belongs to a class of enzymes called ferroxidases - enzymes that oxidise iron from its ferrous (Fe2+) form to its ferric (Fe3+) form. This reaction is critical for iron metabolism because only ferric iron can bind to transferrin, the protein that transports iron through the blood to the bone marrow and other tissues. Without adequate caeruloplasmin activity, iron cannot be properly mobilised from storage sites, leading to iron accumulation in tissues and paradoxical iron-deficiency anaemia.

Beyond its role in copper and iron metabolism, caeruloplasmin functions as an antioxidant, neutralising free radicals and protecting cells from oxidative damage. It also participates in the acute-phase inflammatory response - meaning its levels rise during infection, inflammation, and tissue injury.

The most important clinical application of caeruloplasmin testing is in the diagnosis of Wilson's disease, a rare genetic disorder of copper metabolism that can cause devastating liver and neurological damage if left untreated.

Why Is Caeruloplasmin Tested?

Caeruloplasmin is a specialised test, requested less frequently than general liver markers but critically important in specific clinical scenarios:

• Diagnosing Wilson's disease: This is the primary indication. Wilson's disease is an autosomal recessive condition caused by mutations in the ATP7B gene, which impairs the liver's ability to incorporate copper into caeruloplasmin and excrete excess copper into bile. The result is toxic copper accumulation in the liver, brain, kidneys, and cornea.
• Investigating unexplained liver disease in young people: Wilson's disease typically presents between ages 5 and 35. Any young patient with unexplained hepatitis, cirrhosis, or acute liver failure should be tested for caeruloplasmin.
• Evaluating neuropsychiatric symptoms: Wilson's disease can present with tremor, dystonia, dysarthria (slurred speech), personality changes, depression, psychosis, and declining academic performance. Caeruloplasmin testing is essential in the diagnostic workup.
• Investigating Kayser-Fleischer rings: These are greenish-brown rings visible at the periphery of the cornea on slit-lamp examination, caused by copper deposition. Their presence alongside low caeruloplasmin is virtually diagnostic of Wilson's disease.
• Copper metabolism assessment: Caeruloplasmin is measured alongside serum copper and 24-hour urinary copper to evaluate copper status.
• Evaluating iron overload with normal ferritin: Acaeruloplasminaemia (absence of caeruloplasmin) causes iron accumulation, and caeruloplasmin testing may be relevant in atypical iron overload presentations.
• Monitoring Wilson's disease treatment: Serial caeruloplasmin measurements help track treatment response.

Normal Caeruloplasmin Ranges

Caeruloplasmin is measured in grams per litre (g/L) or milligrams per decilitre (mg/dL):

Group	Normal Range (g/L)	Normal Range (mg/dL)
Adults	0.20–0.60 g/L	20–60 mg/dL
Children (1–12 years)	0.30–0.65 g/L	30–65 mg/dL
Neonates (under 6 months)	0.05–0.30 g/L	5–30 mg/dL (low levels are physiological)
Pregnancy	Up to 0.80 g/L	Up to 80 mg/dL (oestrogen-driven increase)

In Wilson's disease, caeruloplasmin is typically below 0.20 g/L (20 mg/dL), and often below 0.10 g/L (10 mg/dL). However, approximately 5–15% of Wilson's disease patients have caeruloplasmin within the low-normal range, so a normal result does not entirely exclude the diagnosis if clinical suspicion is high.

Neonates have naturally low caeruloplasmin levels because the liver takes several months to reach full production capacity. Levels normalise by 6–12 months of age.

What Do High Caeruloplasmin Levels Mean?

Elevated caeruloplasmin is less diagnostically specific than low levels but occurs in several contexts:

Common causes of high caeruloplasmin

• Acute-phase response: Caeruloplasmin is a positive acute-phase reactant, meaning levels rise during infection, inflammation, surgery, trauma, and burns. This is the most common cause of elevated caeruloplasmin.
• Pregnancy: Oestrogen stimulates hepatic caeruloplasmin production. Levels can double during pregnancy and while taking oral contraceptives or hormone replacement therapy.
• Oral contraceptives and HRT: Oestrogen-containing medications raise caeruloplasmin.
• Rheumatoid arthritis and other chronic inflammatory conditions: Chronic inflammation drives sustained caeruloplasmin elevation.
• Lymphoma and certain cancers: Malignancy-associated inflammation can raise caeruloplasmin.
• Smoking: Chronic inflammation from smoking can modestly elevate caeruloplasmin.
• Copper supplementation: Excessive copper intake raises both serum copper and caeruloplasmin.

Important clinical caveat: In Wilson's disease, caeruloplasmin may appear falsely normal or even elevated if the patient has concurrent inflammation or infection. This is why Wilson's disease diagnosis relies on a combination of caeruloplasmin, serum copper, 24-hour urinary copper, genetic testing, and clinical findings - not caeruloplasmin alone.

What Do Low Caeruloplasmin Levels Mean?

Low caeruloplasmin is the finding of greatest clinical importance and should always prompt further investigation:

Wilson's disease

This is the most important cause. Wilson's disease affects approximately 1 in 30,000 people worldwide and is a treatable condition - but if missed, it can cause irreversible liver failure, permanent neurological damage, and death. Key features include:

• Low caeruloplasmin (usually below 0.20 g/L)
• Low total serum copper but elevated "free" (non-caeruloplasmin-bound) copper
• Elevated 24-hour urinary copper excretion (typically above 1.6 µmol/day, or 100 µg/day)
• Kayser-Fleischer rings on slit-lamp examination (present in 95% of neurological Wilson's disease)
• Liver disease ranging from asymptomatic enzyme elevation to fulminant hepatic failure
• Neuropsychiatric symptoms: tremor, dystonia, parkinsonism, personality change, depression

Other causes of low caeruloplasmin

• Menkes disease: A rare X-linked recessive disorder of copper absorption affecting male infants. Presents with failure to thrive, kinky hair, neurological deterioration, and very low caeruloplasmin and copper levels.
• Acaeruloplasminaemia: An extremely rare autosomal recessive condition where caeruloplasmin is completely absent. Despite being a copper-carrying protein disorder, the primary consequence is iron accumulation in the brain, liver, and pancreas, causing neurodegeneration, diabetes, and retinal degeneration.
• Severe liver disease: Advanced cirrhosis (from any cause) can reduce caeruloplasmin production, as the liver is the sole production site.
• Protein-losing enteropathy: Conditions causing excessive protein loss through the gut can reduce caeruloplasmin.
• Nephrotic syndrome: Massive protein loss in urine can lower caeruloplasmin.
• Severe malnutrition: Protein-calorie malnutrition reduces hepatic protein synthesis.
• Copper deficiency: Rare in developed countries but can occur with excessive zinc supplementation (zinc competes with copper for absorption), prolonged parenteral nutrition without copper, and after bariatric surgery.

How to Manage Abnormal Caeruloplasmin

Management depends entirely on the underlying cause:

If Wilson's disease is diagnosed

Wilson's disease is a lifelong condition requiring ongoing treatment, but with early diagnosis and adherence to therapy, patients can lead normal lives:

• Copper chelation therapy: D-penicillamine and trientine bind excess copper, promoting its urinary excretion. These drugs must be taken for life.
• Zinc therapy: Zinc acetate blocks intestinal copper absorption and is often used as maintenance therapy after initial chelation, or as first-line treatment in pre-symptomatic patients.
• Low-copper diet: Avoid high-copper foods including liver, shellfish (especially oysters and crab), chocolate, nuts, mushrooms, and organ meats. Drinking water from copper pipes should be avoided.
• Liver transplantation: Curative in cases of fulminant liver failure or decompensated cirrhosis that does not respond to medical therapy.
• Family screening: All first-degree relatives of a Wilson's disease patient should be screened with caeruloplasmin, liver function tests, and serum copper. Genetic testing of the ATP7B gene can confirm carrier status.

If caeruloplasmin is elevated (acute-phase response)

• Address the underlying cause of inflammation or infection.
• If on oestrogen-containing medication, consider this as a benign explanation.
• Repeat testing after the acute illness has resolved for a true baseline level.

General copper and liver health

• Balanced diet: Copper is an essential trace element, and dietary copper intake of 1.2 mg/day is recommended for UK adults. Most people achieve this through a varied diet.
• Avoid excessive zinc supplementation: High-dose zinc supplements (above 40 mg/day) can deplete copper stores by blocking intestinal absorption.
• Support liver health: Limit alcohol, maintain a healthy weight, and exercise regularly.

When Should You Get Tested?

Caeruloplasmin testing is not part of routine health screening but should be considered if you:

• Have unexplained liver disease, particularly if you are under 40
• Experience neurological symptoms such as tremor, difficulty with coordination, or speech changes
• Have personality changes or psychiatric symptoms with no clear cause
• Have been found to have Kayser-Fleischer rings on eye examination
• Have a family member diagnosed with Wilson's disease
• Have unexplained haemolytic anaemia (Wilson's disease can present with acute haemolysis)
• Have persistently abnormal liver function tests without an identified cause

Which Lola Health Tests Include Caeruloplasmin?

Caeruloplasmin is available in Lola Health's most comprehensive panels:

• Peak Insights (70 Biomarkers) — Our most comprehensive panel, including caeruloplasmin alongside full liver function, metabolic, and nutritional markers.

If you are specifically concerned about copper metabolism or Wilson's disease, we recommend discussing your results with a hepatologist or metabolic medicine specialist.

All Lola Health tests use a venous blood draw at one of our nationwide partner clinics. Results are reviewed by a doctor and returned within 4 working days.