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.

Last updated 31 Aug 2026

CSF Protein Unit Converter

mg/dL → mg/L
450mg/LExample

CSF protein 45 mg/dL

Formula and conversion factor

mg/L = mg/dL × 10
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

SampleTypical range (mg/dL)Typical range (mg/L)
Lumbar CSF, adult15 – 45150 – 450
Ventricular CSF5 – 1550 – 150
Cisternal CSF10 – 25100 – 250
Neonateup to ≈ 100up to ≈ 1000
Elderly adultsomewhat higher than younger adults—
Protein is lowest in ventricular fluid and highest in lumbar fluid, reflecting where along the CSF pathway more protein has diffused in from the meninges and blood.

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.

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References

  1. Seehusen DA, Reeves MM, Fomin DA. Cerebrospinal fluid analysis. Am Fam Physician. 2003;68(6):1103–8.
  2. Wildemann B, Oschmann P, Reiber H (eds). Laboratory Diagnosis in Neurology, 2nd ed. Thieme.