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White Blood Cell Count in Cerebrospinal Fluid (WBC CSF)

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

This test measures the number of white blood cells found in your cerebrospinal fluid (the fluid surrounding your brain and spinal cord). It helps assess for infections, inflammation, or other conditions affecting the central nervous system.

Quick summary

["A high or low WBC count in CSF may signal underlying health concerns needing further evaluation."]

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

Key facts at a glance

LOINC
46089-9
Short code
WBC tube3 # CSF
Synonyms
WBC tube3 # CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like headaches, neck stiffness, fever, confusion, or neurological issues. It’s often used to diagnose conditions such as meningitis, encephalitis, or other infections/inflammations in the brain or spinal cord.

How the Test Works

A small amount of cerebrospinal fluid is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then examined under a microscope to count the white blood cells.

What to Expect Before the Test

You may be asked to fast or avoid certain medications before the procedure, depending on your provider’s instructions. Inform them about any medications, allergies, or recent illnesses.

What to Expect During the Test

The procedure involves lying on your side with your knees bent. A needle is inserted into your lower back to collect the fluid. You may feel pressure or a slight ache, but it’s generally well-tolerated.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: csf

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated white blood cell count in CSF often indicates an infection (e.g., bacterial or viral meningitis), inflammation (e.g., multiple sclerosis), or other immune responses in the central nervous system. A normal count helps rule out these conditions.

Short name

WBC CSF

Frequently asked questions

What does a high WBC count in CSF mean?
A high WBC count can suggest an infection, autoimmune disease, or other inflammatory processes in the brain or spinal cord. Your provider will review your symptoms and other test results to determine the cause.
What does a low WBC count in CSF mean?
A low WBC count is less common but may indicate conditions like Guillain-Barré syndrome, certain types of brain tumors, or other rare neurological disorders. Further testing is needed to clarify the reason.
How often should this test be repeated?
Your provider will decide how often to repeat this test based on your symptoms, test results, and overall health. Follow-up may be needed if initial results are abnormal or if symptoms persist.
  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