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Cerebrospinal Fluid Cell Differential Count (with Red Blood Cell Count)

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

This test measures the types and numbers of white blood cells, as well as red blood cells, in your cerebrospinal fluid (CSF). It helps assess conditions affecting the brain and spinal cord.

Quick summary

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

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

Key facts at a glance

LOINC
13331-4
Short code
CD2CD26
Synonyms
CD2+CD26+ Cells NFr Bld
Category
chemistry
Sample
whole-blood
Container
EDTA (lavender/purple-top) vacutainer tube, or sodium heparin (green-top) tube for flow cytometry immunophenotyping. ACD (yellow-top) tube is also acceptable.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
Flow cytometry using fluorescently labeled monoclonal antibodies directed against CD2 and CD26 cell surface markers, with subsequent analysis of CD2+CD26+ lymphocyte populations as a percentage of total lymphocytes or cells.
CPT
86355
SNOMED
399145008
Specimen volume
3-5 mL of whole blood for adults; minimum 1 mL for pediatric patients. Specimen volume requirements vary by laboratory; contact testing facility for specific requirements.
Stability
Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C). Refrigeration (2-8°C) may extend stability up to 72 hours for some markers, but CD26 expression can be affected by prolonged storage. Optimal results obtained within 24 hours of collection.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
24–72 hours
Order
routine

Why This Test Is Done

Doctors may order this test to investigate symptoms like headaches, neck stiffness, seizures, confusion, or neurological problems. It’s also used to monitor conditions such as infections, inflammation, or tumors in the central nervous system.

What to Expect Before the Test

No special preparation is needed. You may have a mild headache afterward, but it usually goes away quickly. If you’re on blood thinners or have bleeding disorders, let your doctor know before the procedure.

How the Test Is Performed

A small amount of CSF is collected through a needle inserted into your spine (lumbar puncture). The sample is then sent to the lab for microscopic examination to count and identify different cell types, including red blood cells.

What the Results Mean

Abnormal results may indicate infections (like meningitis), bleeding, inflammation, or other neurological disorders. Your doctor will interpret the results in the context of your symptoms and medical history.

Reference range

Reference ranges for CD2+CD26+ cells vary by laboratory and reference population. Typically reported as a percentage of total lymphocytes or as absolute count per microliter of blood. Values are generally established through flow cytometric immunophenotyping with CD45 gating and lymphocyte subset analysis.N/A

Specimen: whole-blood

No special patient preparation required. Patient should be well-hydrated. Inform the laboratory of any recent infections, immunosuppressive therapy, corticosteroid use, chemotherapy, or hematopoietic stem cell transplantation, as these factors may affect lymphocyte subset distribution.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF Cell & RBC Count

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–2 business days, depending on lab processing times.
What does a normal result mean?
A normal result means your CSF cell count and red blood cell count are within expected ranges for healthy individuals, but this doesn’t rule out all possible causes of symptoms.
Can I drink alcohol before this test?
Avoid heavy alcohol use 24 hours before the test, as it may increase the risk of bleeding during 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