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Cerebrospinal Fluid Sodium and Potassium Profile (Electrolytes)

Published: August 9, 2026Updated: August 16, 2026

This test measures sodium and potassium levels in your cerebrospinal fluid (CSF), which surrounds your brain and spinal cord. These electrolytes help balance fluids and nerve function.

Quick summary

["Electrolyte balance in your brain’s protective fluid can signal potential neurological or health concerns."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
32934-2
Short code
Na-Gl to Na-Prn Angle Skull XR
Synonyms
Na-Gl to Na-Prn Angle Skull XR
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-measured
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test to investigate symptoms like headaches, seizures, nerve damage, or signs of infections, inflammation, or structural issues in the brain or spinal cord. It’s also used to monitor conditions like meningitis, brain tumors, or multiple sclerosis.

What to Expect Before the Test

You’ll likely have a lumbar puncture (spinal tap) where a small needle is inserted into your lower back to collect CSF. The procedure is quick but may cause mild discomfort. No special preparation is needed, but inform your provider about any medications or allergies.

What the Results Mean

Abnormal levels of sodium or potassium in CSF can indicate conditions like infections (e.g., bacterial meningitis), bleeding, or metabolic disorders. For example, low sodium might suggest inflammation, while high potassium could signal nerve or muscle issues.

Common Conditions Monitored

This test helps diagnose or track conditions like meningitis, encephalitis, subarachnoid hemorrhage, or certain neurological disorders. It’s also used to assess the effectiveness of treatments for these conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Electrolyte Imbalance in CSF

Short name

CSF Electrolytes

Frequently asked questions

What causes abnormal sodium or potassium in CSF?
Abnormal levels can result from infections (e.g., bacterial or viral), bleeding into the spinal fluid, inflammation, or metabolic disorders. For example, low sodium may signal inflammation or infection, while high potassium could indicate nerve damage or certain tumors.
How long will it take to get my results?
Results are typically available within 1–2 business days, depending on lab processing. Your healthcare provider will discuss them with you during a follow-up visit.
Can I eat or drink before this test?
No special diet is required, but avoid caffeine or alcohol before the procedure to reduce discomfort. Follow your provider’s instructions for any other restrictions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy