Ceruloplasmin Unit Converter
Ceruloplasmin Unit Converter
Convert ceruloplasmin between mg/dL, g/L, mg/L and µmol/L, and see why a normal level does not exclude Wilson disease.
Ceruloplasmin converter
Mass ⇄ molarCeruloplasmin 28 mg/dL
Formula and conversion factors
mg/L = mg/dL × 10
µmol/L = mg/dL × 0.07576
- ÷ 100
- a decilitre is a tenth of a litre and a gram is 1000 mg, so 28 mg/dL is 0.280 g/L
- 0.0757576
- derived from a molecular mass of 132,000 Da; molar reporting is uncommon and no clinical threshold uses it
- immunoassay
- measures the protein whether or not it carries copper, so apoceruloplasmin is counted and a Wilson patient can read falsely normal
- acute-phase reactant
- hepatic synthesis rises with inflammation, pregnancy and oestrogen, which can lift a low level into the reference range
Worked example
Ceruloplasmin 28 mg/dL
28 ÷ 100 = 0.280 g/L
28 × 10 = 280 mg/L
28 × 0.07576 = 2.12 µmol/L
Within the adult reference interval of 20–35 mg/dL
Thresholds across the units
| mg/dL | g/L | µmol/L | |
|---|---|---|---|
| Adult reference interval | 20 – 35 | 0.200 – 0.350 | 1.52 – 2.65 |
| Low — supports Wilson disease if the picture fits | < 20 | < 0.200 | < 1.52 |
| Strongly suggestive in a compatible presentation | < 10 | < 0.100 | < 0.76 |
Why the level can mislead in Wilson disease
| Situation | Effect on ceruloplasmin | Consequence |
|---|---|---|
| Intercurrent inflammation, pregnancy or oestrogen | Raised | A truly low level is lifted into the reference range |
| Apoceruloplasmin present without copper | Counted by immunoassay | The protein is measured even though it is functionally empty |
| Heterozygous carrier | Often modestly low | A low level alone does not make the diagnosis |
| Wilson disease with active hepatitis | Can be normal | Roughly 5 to 20 per cent of patients have a normal level |
A screening test that cannot stand alone
Ceruloplasmin is reported in mg/dL in the United States and in g/L elsewhere, a factor of 100 apart, and occasionally in mg/L. A molar figure using 0.07576 µmol/L per mg/dL is derived from a molecular mass of 132,000 daltons, but molar reporting is uncommon and no clinical threshold is expressed in it. The protein carries most of the copper in the circulation, around 90 per cent of it, which is why it is used as the first-line screen when Wilson disease is suspected.
The screen is imperfect in both directions, and the false reassurance is the dangerous one. Roughly 5 to 20 per cent of patients with Wilson disease have a ceruloplasmin within the reference range, particularly those presenting with active hepatitis, because ceruloplasmin is an acute-phase reactant. Inflammation, pregnancy and oestrogen all raise hepatic synthesis, and the rise is enough to lift a truly low level into normal territory. A normal ceruloplasmin therefore does not exclude the diagnosis, and where the clinical picture fits, the work-up continues regardless.
The assay adds a further problem. Immunoassays measure the protein whether or not it carries copper, so apoceruloplasmin — the copper-free form that accumulates in Wilson disease — is counted alongside the functional holoenzyme. Enzymatic methods that measure oxidase activity read lower and separate the two, but they are less widely used. This is the mechanism by which a Wilson patient can look falsely normal on a routine report.
A low ceruloplasmin is also not specific to Wilson disease. It falls in Menkes disease, in the rare aceruloplasminaemia, in nephrotic syndrome and protein-losing enteropathy, in severe malnutrition and in advanced liver failure of any cause, where synthetic capacity is lost. Heterozygous carriers are often modestly low without any disease. The diagnosis is therefore made on a composite: 24-hour urinary copper, slit-lamp examination for Kayser-Fleischer rings, serum copper interpreted alongside ceruloplasmin, and frequently ATP7B genetic testing or hepatic copper quantification.
Frequently asked questions
How do I convert ceruloplasmin from mg/dL to g/L?
Divide by 100. A level of 28 mg/dL is 0.280 g/L, or 280 mg/L. The µmol/L figure uses a factor of 0.07576, derived from a molecular mass of 132,000 daltons.
Does a normal ceruloplasmin exclude Wilson disease?
No. Roughly 5 to 20 per cent of patients with Wilson disease have a normal level, particularly those presenting with active hepatitis. It is an acute-phase reactant, so inflammation, pregnancy and oestrogen can lift a low level into the reference range.
Why can the immunoassay read falsely normal?
Immunoassays detect the protein whether or not it carries copper, so copper-free apoceruloplasmin is counted alongside the functional holoenzyme. Enzymatic oxidase methods read lower and distinguish the two, but they are less widely available.
What else lowers ceruloplasmin?
Menkes disease, aceruloplasminaemia, nephrotic syndrome and protein-losing enteropathy, severe malnutrition, and advanced liver failure of any cause. Heterozygous carriers of a Wilson mutation are also often modestly low without having the disease.
What else does the Wilson disease work-up need?
A 24-hour urinary copper collection, slit-lamp examination for Kayser-Fleischer rings, and serum copper read alongside the ceruloplasmin. ATP7B genetic testing and, in difficult cases, hepatic copper quantification complete the assessment.
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References
- European Association for the Study of the Liver. EASL Clinical Practice Guidelines: Wilson’s disease. J Hepatol. 2012;56(3):671–685.
- Schilsky ML, Roberts EA, Bronstein JM, et al. A multidisciplinary approach to the diagnosis and management of Wilson disease: 2022 practice guidance on Wilson disease from the American Association for the Study of Liver Diseases. Hepatology. 2023;77(4):1428–1455.
- Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018.