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CD4 Cell Count in Cerebrospinal Fluid (CSF)

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

This test measures the number of CD4 immune cells (a type of white blood cell) found in your cerebrospinal fluid (CSF). It helps assess immune function in the central nervous system, particularly in conditions affecting the brain and spinal cord.

Quick summary

["CD4 cells in CSF are critical for monitoring immune responses in the brain and spinal cord."]

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

Key facts at a glance

LOINC
51322-6
Short code
CD42CSF
Synonyms
CD42 Cells NFr CSF
Category
chemistry
Sample
csf
Container
Sterile CSF collection tubes; polypropylene tubes with screw caps for flow cytometry; avoid glass tubes
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Flow cytometry immunophenotyping using fluorescently labeled monoclonal antibodies against CD42 (GPIb)
CPT
88184
SNOMED
444326003
Specimen volume
1-2 mL of CSF minimum; 3-5 mL preferred for adequate cell yield and analysis
Stability
Process within 1-2 hours of collection; do not refrigerate if performing flow cytometry; cells rapidly degrade. If delay anticipated, use RPMI or similar transport medium at room temperature and process within 4-6 hours.
Hemolysis max
200
TAT
24–72 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms or conditions that could involve inflammation or immune activity in the central nervous system, such as certain infections (e.g., meningitis), autoimmune diseases (e.g., multiple sclerosis), or neurological disorders. It can also be part of monitoring for conditions like HIV where immune responses in the brain are important.

What to Expect Before the Test

No special preparation is typically needed. You may have a lumbar puncture (spinal tap) where a small needle is inserted into your lower back to collect a sample of CSF. This procedure is usually done in a hospital setting and may cause mild discomfort.

What the Test Results Mean

Lower than expected CD4 cell counts in CSF may indicate immune dysfunction, inflammation, or infection in the central nervous system. Higher counts might suggest certain immune responses or conditions affecting immune cell migration. Always discuss your results with your healthcare provider.

Common Conditions Monitored

This test is often used to diagnose or monitor conditions such as viral meningitis, multiple sclerosis, Guillain-Barré syndrome, or other neurological immune-related disorders. It can also help track the progression or response to treatment in these conditions.

Reference range

Not normally detected or present in very low numbers in normal CSF; reference ranges are laboratory-specific and typically expressed as cells/uL or percentage of total mononuclear cells. Establish local reference range based on healthy controls.N/A

Specimen: csf

No special patient preparation required. Lumbar puncture should be performed under sterile conditions by qualified personnel. Inform patient of procedure risks including headache, infection, and bleeding.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF CD4 Cell Count

Frequently asked questions

What does a low CD4 cell count in CSF mean?
A low CD4 cell count in CSF may suggest an immune response affecting the brain or spinal cord, such as inflammation, infection, or an autoimmune process. Your healthcare provider will consider your overall clinical picture and other test results to interpret this finding.
How is this test different from a blood CD4 count?
This test specifically measures CD4 cells in cerebrospinal fluid, whereas a blood CD4 count measures these cells in your bloodstream. CSF CD4 counts are less frequently used but can provide unique insights into immune activity directly within the central nervous system.
Can this test be done at home?
No, this test requires a lumbar puncture, which is performed in a clinical setting by a healthcare professional. You will need to be monitored during the procedure for safety.
  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