Basophilscsf
A test that measures the number of basophils in the cerebrospinal fluid (CSF), the clear liquid surrounding the brain and spinal cord.
{"Basophils are a type of white blood cell found in very low numbers in normal CSF","Elevated levels may indicate infection, inflammation, or other neurological conditions","This test is part of a complete CSF analysis called cerebrospinal fluid differential"}
Key facts at a glance
- LOINC
- 35072-8
- Short code
- CSF BASO
- Synonyms
- Basophils # CSF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile, leak-proof, conical-bottom polypropylene collection tubes (tube #3 or #4 for cell count, labeled per CLSI guidelines)
- Units
- N/A
- Ref low
- 0
- Ref high
- 0
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Manual microscopic differential cell count using a Neubauer hemocytometer or automated cell counter with cytocentrifuge preparation and Wright-Giemsa or May-Grünwald-Giemsa staining
- CPT
- 89051 (Cell count, miscellaneous body fluids, with cell count differential) or 89050 (Cell count, miscellaneous body fluids)
- SNOMED
- 165346009 | Cerebrospinal fluid specimen (specimen) ; 59533004 | Basophil (cell)
- Specimen volume
- 1-2 mL of CSF for cell count; minimum 0.5 mL acceptable for pediatric or limited samples
- Stability
- CSF cell counts must be performed within 1-2 hours of collection. If delayed, refrigerate at 2-8°C and analyze within 4 hours maximum. Prolonged storage causes cell lysis and inaccurate counts.
- Hemolysis max
- 200
- TAT
- 1–4 hours
- Order
- routine
What is this test?
The CSF basophil count is a laboratory test that measures the number of basophils in the cerebrospinal fluid. Basophils are a type of white blood cell (leukocyte) that play a role in the body's immune response. They contain histamine and other chemicals that are released during allergic reactions and inflammation. This test is typically performed as part of a complete CSF cell count and differential, which examines the different types of cells present in the cerebrospinal fluid.
The test involves collecting a sample of cerebrospinal fluid through a lumbar puncture (spinal tap) procedure. The fluid is then examined under a microscope in a laboratory to count and identify the various cell types present, including basophils, neutrophils, lymphocytes, monocytes, and eosinophils.
Reference range
Basophils are normally absent or extremely rare in cerebrospinal fluid (<1 cell/μL). The presence of basophils in CSF is generally considered clinically significant and should be correlated with the total nucleated cell count and clinical presentation.N/A
No specific fasting required. The patient should remain still during lumbar puncture procedure. Informed consent must be obtained prior to CSF collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
In normal cerebrospinal fluid, basophils are typically absent or present in very low numbers (less than 1% of total cells). The presence of elevated basophils in CSF (basophilia) may indicate various conditions including: parasitic infections of the central nervous system, certain viral or bacterial infections, inflammatory conditions such as meningitis, allergic reactions affecting the meninges, or rarely, certain blood disorders or malignancies involving the nervous system.
This test is rarely performed in isolation and is usually interpreted alongside other CSF findings (including total cell count, protein level, glucose level, and other cell types) to help diagnose the underlying condition affecting the brain or spinal cord.
Frequently asked questions
Why do I need this test?
How is the CSF sample collected?
What do abnormal results mean?
Is the test painful?
Sources
- 1
- 2
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