Cerebrospinal Fluid White Blood Cell Count (Microbiology Screening)
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 identify infections, inflammation, or other conditions affecting the central nervous system.
["A CSF white blood cell count helps diagnose or monitor conditions like meningitis, brain infections, or other neurological issues."]
Key facts at a glance
- LOINC
- 21176-3
- Short code
- CSFVENT
- Synonyms
- Cerebrov Lin Cell CSF Ql Micro
- Category
- chemistry
- Sample
- csf
- Container
- Sterile CSF collection tube (tube 3 or 4 recommended to minimize blood contamination from traumatic tap)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–99 years
- Method
- microscopy-light
- CPT
- 88104
- SNOMED
- 167992002
- Specimen volume
- 1-2 mL of cerebrospinal fluid for cytological examination
- Stability
- Refrigerated at 2-8°C; analyze within 2-4 hours of collection; if delayed, preserve in cytology fixative or refrigerate up to 24 hours
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
Elevated white blood cells in CSF often signal an infection (e.g., bacterial or viral meningitis), an inflammatory process, or a tumor. Lower-than-normal counts may indicate conditions like Guillain-Barré syndrome or certain autoimmune diseases. This test is critical for guiding treatment decisions.
What to Expect Before the Test
No special preparation is needed. You may experience mild discomfort during the lumbar puncture (spinal tap) procedure, where a small needle is inserted into your lower back to collect CSF. Rest assured, this is a standard, safe procedure performed by trained medical professionals.
What the Results Mean
Results are interpreted by your healthcare provider based on your symptoms, medical history, and other tests. Abnormal counts may prompt further investigation, such as additional CSF tests, imaging, or cultures to determine the cause.
Common Causes of Abnormal Results
High white blood cell counts in CSF can be due to infections (e.g., bacterial meningitis), autoimmune diseases (e.g., multiple sclerosis), or trauma. Low counts may occur with certain neurological disorders or after treatment for infections.
Reference range
None detected or rare; presence may indicate intrathecal sampling, CNS instrumentation, or ventricular shunt placementN/A
No special patient preparation required; lumbar puncture performed under sterile conditions by qualified healthcare provider
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CSF WBC Count
Frequently asked questions
How often will I need this test?
What are the risks or side effects of this test?
Can I drink or eat before the test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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