CSF Protein Unit Converter
CSF Protein Unit Converter
Convert CSF total protein between mg/dL and mg/L, with reference ranges by site and age and the albuminocytological dissociation pattern.
CSF Protein Unit Converter
mg/dL → mg/LCSF protein 45 mg/dL
Formula and conversion factor
g/L = mg/dL ÷ 100
- ×10
- mg/dL to mg/L, the standard SI conversion for a concentration reported per decilitre versus per litre
- ÷100
- mg/dL to g/L, useful when a report gives protein in grams per litre
Worked example
CSF protein 45 mg/dL
45 × 10 = 450 mg/L
= 0.45 g/L
Reference ranges by site and age
| Sample | Typical range (mg/dL) | Typical range (mg/L) |
|---|---|---|
| Lumbar CSF, adult | 15 – 45 | 150 – 450 |
| Ventricular CSF | 5 – 15 | 50 – 150 |
| Cisternal CSF | 10 – 25 | 100 – 250 |
| Neonate | up to ≈ 100 | up to ≈ 1000 |
| Elderly adult | somewhat higher than younger adults | — |
Reading a CSF protein result
Converting is straightforward: mg/dL multiplied by 10 gives mg/L, and mg/dL divided by 100 gives g/L. The normal adult range for lumbar CSF is roughly 15 to 45 mg/dL, or 150 to 450 mg/L, and it is not a single fixed number — protein is lower in ventricular and cisternal fluid than in lumbar fluid, and higher in neonates, who can normally reach up to about 100 mg/dL, and in the elderly, where protein rises modestly with age.
A very high protein with a normal or near-normal cell count — albuminocytological dissociation — is the classic CSF finding in Guillain-Barré syndrome, reflecting nerve root inflammation that raises protein without a matching cellular response. It is worth remembering that this pattern may still be normal in the first week of illness, so a normal early lumbar puncture does not exclude the diagnosis.
Froin’s syndrome, with markedly raised protein together with xanthochromia, is a rarer cause and reflects spinal block obstructing CSF flow, most often from a spinal tumour or severe stenosis. A traumatic tap also raises protein, by roughly 1 mg/dL for every 1000 red cells introduced, which is worth allowing for before over-interpreting a mildly raised result in a bloody sample.
Frequently asked questions
How do I convert CSF protein from mg/dL to mg/L?
Multiply by 10. A CSF protein of 45 mg/dL is 450 mg/L. To convert to g/L instead, divide the mg/dL value by 100.
What is a normal CSF protein?
Roughly 15 to 45 mg/dL (150 to 450 mg/L) in adult lumbar CSF. Ventricular and cisternal fluid run lower, and neonates and the elderly run somewhat higher.
What is albuminocytological dissociation?
A markedly raised CSF protein with a normal or near-normal white cell count. It is the classic finding in Guillain-Barré syndrome, though it may still be normal in the first week of illness.
How much does a traumatic tap raise CSF protein?
Roughly 1 mg/dL for every 1000 red cells introduced into the sample. This should be allowed for before attributing a mildly raised protein to disease in a visibly bloody tap.
Related calculators
References
- Seehusen DA, Reeves MM, Fomin DA. Cerebrospinal fluid analysis. Am Fam Physician. 2003;68(6):1103–8.
- Wildemann B, Oschmann P, Reiber H (eds). Laboratory Diagnosis in Neurology, 2nd ed. Thieme.