How do I convert Potassium (CSF) from mmol/L to mg/dL?

mg/dL = mmol/L × 3.91. In the other direction: mmol/L = mg/dL × 0.2558.

What is the reference range of Potassium (CSF)?

For adults the range is 2.6 – 3.15 mmol/L (Pirke, Wisser, Mertin (1972): Elektrolytkonzentrationen in Liquor und Serum, Z Klin Chem Klin Biochem 10:462-466 (HU Berlin edoc)). Reference ranges differ between laboratories and partly by sex and age; use the range printed on your lab report.

Which units are used for Potassium (CSF)?

Common units are mmol/L, g/L, mg/dL, mg/L, µmol/L.

Urine & CSF

Potassium (CSF) unit converter

Potassium in cerebrospinal fluid

Also known as: CSF potassium, Liquorkalium, Kalium im Liquor, Potassium in cerebrospinal fluid

Converter

Enter a value in any unit and all other units fill in.

mmol/L = mEq/L g/L mg/dL mg/L µmol/L

Worked example

2.875 mmol/L (middle of the reference range) = 0.112 g/L

Conversion formulas

g/L	g/L = mmol/L × 0.0391	mmol/L = g/L × 25.58
mg/dL	mg/dL = mmol/L × 3.91	mmol/L = mg/dL × 0.2558
mg/L	mg/L = mmol/L × 39.1	mmol/L = mg/L × 0.02558
µmol/L	µmol/L = mmol/L × 1000	mmol/L = µmol/L × 0.001

Good to know

Potassium in cerebrospinal fluid is reported in mmol/L or mEq/L, which are numerically identical.

1 mmol/L = 1 mEq/L; CSF potassium is much lower than serum potassium.
CSF (cerebrospinal fluid) values are only meaningful together with a blood sample taken at the same time and the other CSF results.

Reference range

Unit	Adults
mmol/L = mEq/L	2.6 – 3.15
g/L	0.1017 – 0.1232
mg/dL	10.17 – 12.32
mg/L	101.7 – 123.2
µmol/L	2600 – 3150

Source: Pirke, Wisser, Mertin (1972): Elektrolytkonzentrationen in Liquor und Serum, Z Klin Chem Klin Biochem 10:462-466 (HU Berlin edoc) · Last reviewed: 2026-10-19

Note from the source: 2.60-3.15 mmol/L (96th-percentile limits, 102 samples, flame photometry; study from 1972). CSF potassium is held within narrower limits than serum potassium