Cerebrospinal Fluid Cell Differential Count
This test measures the types and numbers of white blood cells in your cerebrospinal fluid (CSF), which surrounds your brain and spinal cord. It helps diagnose conditions affecting the central nervous system.
["Understanding your CSF cell count can help identify infections, inflammation, or other issues in your brain and spinal cord."]
Key facts at a glance
- LOINC
- 103666-4
- Short code
- CD200BMFC
- Synonyms
- Cells.CD200 NFr Mar FC
- Category
- chemistry
- Sample
- serum
- Container
- Sterile bone marrow aspirate collected in sodium heparin (green-top) or EDTA (purple-top) anticoagulated tubes for flow cytometry analysis. Transport tubes appropriate for flow cytometric immunophenotyping.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 88184
- SNOMED
- 122548005
- Specimen volume
- 1-3 mL of bone marrow aspirate in anticoagulant tube; minimum 0.5 mL acceptable for pediatric or dry-tap specimens.
- Stability
- Specimen should be processed within 24 hours of collection when stored at room temperature (18-25°C). Refrigerated storage (2-8°C) may extend viability up to 48 hours but is not preferred as it may affect antigen expression. Do not freeze.
- 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 problems. It’s often done when conditions like meningitis, multiple sclerosis, or brain tumors are suspected.
How the Test Works
A small amount of CSF is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then examined under a microscope to count and identify different types of white blood cells, such as neutrophils, lymphocytes, and monocytes.
Sample Preparation and Testing
The collected CSF is sent to a lab where it is mixed with a stain to highlight cell types. A trained technician then counts and categorizes the cells using a microscope.
What to Expect Before the Test
You may receive a local anesthetic at the injection site to minimize discomfort. You’ll lie on your side with your back bent slightly, and the doctor will insert a needle into your lower back to collect the fluid. You may feel pressure or a mild ache, but it usually doesn’t cause significant pain.
Reference range
Reference values are laboratory-specific and depend on antibody clones, fluorochrome panels, and gating strategies used. CD200 expression is reported as percentage of positive cells within relevant leukocyte populations. Typically, normal bone marrow shows low/absent CD200 on most hematopoietic precursors with variable expression on B-cell subsets. Results should be interpreted alongside morphology and concurrent flow cytometry panels.N/A
No special patient preparation is required for bone marrow aspiration. Informed consent must be obtained prior to the procedure. Patients on anticoagulants should be evaluated for bleeding risk.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal cell counts can indicate infections (e.g., bacterial or viral meningitis), inflammatory diseases (e.g., multiple sclerosis), bleeding in the brain, or other neurological conditions. For example, a high number of neutrophils might suggest bacterial infection, while lymphocytes could indicate viral causes or autoimmune disorders.
Short name
CSF Cell Count with Differential
Frequently asked questions
How long does it take to get results?
What does a normal result mean?
Can I eat or drink before 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 16, 2026. · Read our editorial policy