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B-cell count in cerebrospinal fluid (CD19+ cells)

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

This test measures the number of B-cells (a type of white blood cell) in your cerebrospinal fluid (CSF), which surrounds your brain and spinal cord. It helps assess immune activity in the central nervous system.

Quick summary

["B-cell presence in CSF may indicate inflammation, infection, or immune disorders in the brain/spinal cord."]

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

Key facts at a glance

LOINC
51353-1
Short code
CSFCD19CD58
Synonyms
CD19+CD58+ Cells NFr CSF
Category
chemistry
Sample
csf
Container
Sterile CSF collection tubes (polypropylene); specific tube requirements depend on flow cytometry panel used; typically collected sequentially into numbered tubes with tube 3-4 preferred for cell-based analyses to minimize blood contamination
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
Flow cytometry (immunophenotyping) using fluorescently-labeled monoclonal antibodies against CD19 and CD58 surface markers, typically with multicolor panel analysis on cerebrospinal fluid cells
CPT
88184 (Flow cytometry, cell surface, cytoplasmic, or nuclear marker, technical component only; first marker) with additional CPT codes for each additional marker (88185 x2 for CD19 and CD58) and 88187-88189 for interpretation as applicable
SNOMED
445532009 (Cerebrospinal fluid specimen) combined with procedure codes for flow cytometry immunophenotyping
Specimen volume
1-3 mL of CSF minimum; larger volumes (5-10 mL) preferred for adequate cell yield in flow cytometry analysis
Stability
Process specimen within 1-2 hours of collection for optimal cell viability. If delayed, store at 2-8°C and process within 4 hours. Do not freeze. Fixation protocols may be used per laboratory-specific procedures.
Hemolysis max
200
TAT
4–48 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like headaches, neck stiffness, confusion, or neurological problems that could suggest an immune-related condition affecting the brain or spinal cord. It’s also used to monitor certain treatments for conditions like multiple sclerosis or autoimmune diseases.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your lumbar spine to collect CSF. The procedure is quick but may cause mild discomfort. You’ll lie on your side for a few minutes afterward to prevent any spinal fluid leakage.

What the Results Mean

Results show the count of B-cells (CD19+) in your CSF. Elevated levels may suggest conditions like meningitis, certain cancers (e.g., lymphoma), or immune disorders. Low or normal levels may indicate no significant immune activity in your CNS, but further testing would be needed to confirm.

Common Conditions This Test Helps Diagnose

This test can help diagnose or monitor conditions such as chronic inflammatory diseases, infections (e.g., viral meningitis), or rare neurological disorders linked to abnormal immune responses in the CNS.

Reference range

Reference ranges vary by laboratory; typically reported as percentage of total lymphocytes or as absolute count per microliter. CD19+ B-lymphocytes are normally rare or absent in CSF. Clinical interpretation should be performed in conjunction with other CSF parameters.N/A

Specimen: csf

No special patient preparation required. CSF collection is performed by lumbar puncture by a qualified healthcare provider under sterile conditions. Inform the ordering physician of any bleeding disorders, anticoagulant use, or allergies to local anesthetics prior to the procedure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Elevated B-cell counts in CSF often correlate with immune-mediated or infectious processes in the central nervous system. It’s particularly useful in distinguishing between inflammatory, infectious, or neoplastic causes of neurological symptoms. Low or normal counts may rule out certain immune-related conditions but don’t rule out all possibilities—additional tests may be needed.

Short name

CSF B-cell count

Frequently asked questions

What does a high B-cell count in CSF mean?
A high count could signal an immune response, such as chronic inflammation, an infection, or a rare neurological disorder. Your doctor will consider your symptoms, medical history, and other test results to interpret the results.
Does this test require fasting?
No fasting is required for this test. It’s a simple procedure where CSF is collected directly from your spine.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will discuss them with you during your follow-up visit.
  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