Skip to content

Cerebrospinal Fluid Cell Count (with Differential)

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

This test measures the number of cells in your cerebrospinal fluid (CSF), including white blood cells, red blood cells, and sometimes specific types of white blood cells (differential count). It helps assess conditions affecting the brain and spinal cord.

Quick summary

["A CSF cell count helps diagnose infections, bleeding, or inflammation in the central nervous system."]

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

Key facts at a glance

LOINC
20594-8
Short code
CD2
Synonyms
CD2 Cells NFr Spec
Category
chemistry
Sample
serum
Container
Lavender-top (EDTA) tube for whole blood flow cytometry; for serum, red-top or serum separator tube (SST)
Units
N/A
Ref low
80
Ref high
90
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
Flow cytometry using fluorescein (FITC) and phycoerythrin (PE)-conjugated monoclonal antibodies against CD2 surface marker, analyzed on a flow cytometer
CPT
86355
SNOMED
115670000
Specimen volume
3-5 mL whole blood in EDTA; minimum 1 mL for pediatric samples
Stability
Whole blood in EDTA is stable for up to 24 hours at room temperature (18-25°C) for flow cytometry; do not refrigerate or freeze. Serum should be separated and analyzed within 4 hours of collection.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms like headaches, neck stiffness, confusion, fever, or neurological issues. It’s often used to investigate conditions such as meningitis, encephalitis, subarachnoid hemorrhage, or other brain/spinal cord problems.

What to Expect Before the Test

You’ll likely have a small needle inserted into your lumbar spine (lower back) to collect CSF. You may feel pressure or a slight pinch, but it’s usually quick and painless. Lie on your side with your knees bent to help with the procedure.

During the Test

The collected CSF is sent to a lab for analysis. The test may include counting cells under a microscope or additional tests (like protein or glucose) depending on your symptoms and doctor’s orders.

What the Results Mean

High cell counts (especially white blood cells) may indicate infection, inflammation, or bleeding. Low counts could suggest a blockage or other rare conditions. Your doctor will interpret results in the context of your symptoms and medical history.

Reference range

Reference ranges for CD2+ T-cells vary by laboratory and reporting units (percentage or absolute count). Typically, CD2+ cells represent approximately 80-90% of peripheral blood lymphocytes. Always refer to the individual laboratory's reference interval provided with the report.N/A

Specimen: serum

No fasting is required. Patients should be well-hydrated. Recent corticosteroid therapy, chemotherapy, or immunosuppressive medications may affect lymphocyte subset counts and should be noted on the requisition.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for diagnosing neurological disorders. Elevated white blood cells often point to infections (e.g., bacterial or viral meningitis), while red blood cells may suggest bleeding. Differential counts help identify specific types of white blood cells involved in immune responses or inflammation.

Short name

CSF Cell Count

Frequently asked questions

What causes abnormal CSF cell counts?
Abnormal CSF cell counts can result from infections (like meningitis), bleeding into the spinal fluid (e.g., subarachnoid hemorrhage), inflammatory conditions, or rare genetic disorders. Your doctor will consider your symptoms and other test results to determine the cause.
How long does it take to get results?
Results are typically available within 1–2 business days, depending on lab processing times. Your doctor will contact you once they’re ready, especially if further testing is needed.
Can I eat or drink before this test?
No special preparation is needed for this test. You can eat, drink, and take medications as usual. However, inform your doctor if you’re on blood-thinning medications, as they may affect the procedure.
  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