Cerebrospinal fluid cell differential count
This test measures the types and numbers of white blood cells (cells that fight infection) in your cerebrospinal fluid (CSF), which surrounds your brain and spinal cord. It helps identify causes of inflammation, infection, or other issues in the central nervous system.
["Assists in diagnosing conditions affecting the brain and spinal cord."]
Key facts at a glance
- LOINC
- 38513-8
- Short code
- CD2CD3
- Synonyms
- CD2+CD3+ Cells # Spec
- Category
- chemistry
- Sample
- serum
- Container
- EDTA (lavender/purple top) vacuum blood collection tube for flow cytometry; sodium heparin (green top) tube is an acceptable alternative for immunophenotyping
- Units
- N/A
- Ref low
- 1200
- Ref high
- 2500
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Flow cytometry using fluorochrome-conjugated monoclonal antibodies (CD2-FITC and CD3-PE) with whole blood lysis and multiparameter immunophenotyping
- CPT
- 86359
- SNOMED
- 26958001
- Specimen volume
- 3-5 mL of whole blood for adults; minimum 1 mL for pediatric patients
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C); do not refrigerate as cold-induced apoptosis may alter lymphocyte subset counts. If delayed, follow laboratory-specific validated stability protocols.
- Hemolysis max
- 50
- Lipemia max
- 100
- Icterus max
- 20
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
CSF cell counts are critical for ruling out or confirming conditions like meningitis, encephalitis, or multiple sclerosis. Abnormal cell types (e.g., high lymphocytes, neutrophils, or red blood cells) can signal specific infections, bleeding, or autoimmune diseases.
Common Conditions Evaluated
This test often follows a lumbar puncture (spinal tap) to check for infections (e.g., bacterial or viral meningitis), blood in the CSF (e.g., subarachnoid hemorrhage), or inflammatory diseases (e.g., Guillain-Barré syndrome).
Sample Collection and Preparation
A small amount of CSF is collected via a needle inserted into your lower back. The sample is then examined under a microscope to count and identify cell types (e.g., neutrophils, lymphocytes, monocytes).
Sample Types and Methods
The test uses direct microscopic analysis of CSF, which may include staining techniques to distinguish cell types. Results are reported as absolute counts of each cell type (e.g., neutrophils: 5–20 cells/µL; lymphocytes: 0–8 cells/µL).
Reference range
Reference ranges vary by laboratory and population; absolute CD2+CD3+ lymphocyte counts are age-dependent. Typical adult ranges: 1200-2500 cells/μL or 65-85% of total lymphocytes. Pediatric values are higher at birth and decline with age to adult levels by adolescence.N/A
No fasting required. Patient should be well-hydrated. Recent vaccinations, infections, immunosuppressive therapy, or corticosteroids may affect results and should be documented. Avoid strenuous exercise immediately prior to collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal cell counts or patterns (e.g., high neutrophils in bacterial meningitis, high lymphocytes in viral infections) guide treatment decisions. For example, elevated red blood cells may indicate bleeding, while abnormal monocytes could signal conditions like sarcoidosis or tuberculosis.
Short name
CSF Cell Count & Differential
Frequently asked questions
What does a normal result mean?
What if my test shows unusual cell types?
How often should I get this 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 14, 2026. · Read our editorial policy