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Cerebrospinal Fluid Cell Differential Count

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

This test examines the types and numbers of cells found in your cerebrospinal fluid (CSF), which surrounds your brain and spinal cord. It helps identify infections, inflammation, or other conditions affecting the central nervous system.

Quick summary

["Understanding your CSF cell count can help diagnose or monitor neurological conditions."]

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

Key facts at a glance

LOINC
106964-0
Short code
CD2CD3
Synonyms
CD2+CD3+ Cells NFr Bld FC
Category
chemistry
Sample
whole-blood
Container
EDTA (purple-top) tube for whole-blood flow cytometry; alternatively, ACD (yellow-top) tube or sodium heparin (green-top) tube may be used depending on laboratory protocol
Units
N/A
Ref low
1200
Ref high
2400
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
flow-cytometry
CPT
86359
SNOMED
39579005
Specimen volume
3-5 mL of whole blood for adults; 1-3 mL for pediatric patients; minimum 1 mL required for accurate flow cytometric analysis
Stability
Specimen should be processed within 24 hours of collection when stored at room temperature (18-25°C). Refrigeration at 2-8°C may extend stability to 48 hours for some markers but may affect viability and antigen expression. Ideally processed within 6-12 hours of collection for optimal results.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Does This Test Measure?

The test looks at two main parts: the total number of cells in your CSF and the breakdown (differential) of those cells into different types, such as white blood cells (neutrophils, lymphocytes, monocytes) and red blood cells. This helps determine if there’s an infection, bleeding, or other abnormalities.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like headaches, neck stiffness, confusion, or neurological issues. It’s also used to monitor conditions like meningitis, multiple sclerosis, or brain tumors.

Sample Collection and Preparation

A small amount of CSF is collected through a procedure called a lumbar puncture (spinal tap). The sample is then analyzed under a microscope to count and identify the different cell types.

Common Conditions Monitored or Diagnosed

This test helps diagnose infections (like bacterial or viral meningitis), blood in the CSF (from bleeding), inflammatory diseases (such as multiple sclerosis), or other neurological disorders affecting cell counts.

Reference range

Reference ranges for CD2+CD3+ lymphocytes vary by laboratory and age. Adult reference range is typically 1200-2400 cells/µL or 60-85% of total lymphocytes. Age-adjusted pediatric reference ranges are essential for accurate interpretation.N/A

Specimen: whole-blood

No special patient preparation is required. Patients should inform their healthcare provider of any recent vaccinations, infections, immunosuppressive therapy, or corticosteroid use, as these factors may affect lymphocyte counts and subset distribution.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF Cell Count & Differential

Frequently asked questions

How long does it take to get results?
Results are typically available within 1 to 2 business days, depending on lab processing times.
What does a normal result mean?
A normal result usually shows a low total cell count with mostly normal-looking cells (mostly lymphocytes or monocytes). However, reference ranges can vary by lab, so your doctor will interpret results in the context of your symptoms and medical history.
Can I eat or drink before this test?
You may need to fast or avoid certain foods/drinks for up to 8 hours before the procedure, depending on your doctor’s instructions. Follow your healthcare provider’s specific guidelines 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