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Cerebrospinal Fluid White Blood Cell Count (with Differential Analysis)

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

This test measures the number of white blood cells in your cerebrospinal fluid (CSF), which is 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 white blood cell count in CSF may signal an underlying issue needing further medical evaluation."]

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

Key facts at a glance

LOINC
76674-1
Short code
WBC tube1 # CSF
Synonyms
WBC tube1 # 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 doctor may order this test if you have symptoms like headaches, neck stiffness, fever, confusion, or neurological problems. It’s also used to monitor conditions such as meningitis, brain tumors, or multiple sclerosis.

What to Expect Before the Test

You’ll receive a spinal tap (lumbar puncture) where a small needle is inserted into your lower back to collect CSF. You may feel mild pressure or discomfort, but it’s usually quick and painless. Rest for a few hours afterward.

What the Results Mean

Results are interpreted based on your symptoms and medical history. Elevated white blood cells often indicate infection (e.g., bacterial or viral meningitis), while lower counts may suggest bleeding or other conditions. Your doctor will discuss findings with you.

Common Conditions Monitored

This test helps diagnose or track conditions like meningitis, encephalitis, subarachnoid hemorrhage, or certain brain diseases. It’s also used to check for abnormal immune responses in the central nervous system.

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.

◆Associated findings1

Short name

CSF WBC Count

Frequently asked questions

What causes abnormal CSF white blood cell counts?
Abnormal counts can result from infections (e.g., meningitis), immune disorders (e.g., multiple sclerosis), bleeding into the CSF, or tumors. Your doctor will consider your symptoms and other test results to determine the cause.
How often will I need this test?
Frequency depends on your condition. Some patients need retests weekly or monthly to monitor progression or response to treatment. Your doctor will guide you on follow-up schedules.
Can I eat or drink before the test?
You may drink water but avoid solid foods for a few hours before the procedure. Follow your doctor’s specific instructions to ensure accurate results.
  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