Cd21cellsnfrspec
Key facts at a glance
- LOINC
- 38419-8
- Short code
- CD21
- Synonyms
- CD21 Cells NFr Spec
- Category
- chemistry
- Sample
- serum
- Container
- Lavender-top (EDTA) tube for blood specimens; sterile container for other specimen types (e.g., bone marrow, tissue, CSF). For serum-based assays: red-top or serum separator tube.
- Units
- N/A
- Ref low
- 5
- Ref high
- 15
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Flow cytometry using fluorescently labeled monoclonal antibodies against CD21 (CR2) surface marker, typically with lymphocyte gating strategy (CD45/SSC) and enumeration as percentage and absolute count
- CPT
- 86355 (B cells, total count); 86356 (Mononuclear cell antigen, each) or 86359 (T cells, total count) may apply depending on panel composition
- SNOMED
- 14298001 | B-lymphocyte (cell); 397540003 | CD21 antigen (substance)
- Specimen volume
- Minimum 1-3 mL whole blood for peripheral blood enumeration; volume varies by specimen source
- Stability
- Whole blood: 24-48 hours at room temperature (20-25°C); do not refrigerate as cold may affect cell viability and marker expression. Process within 24 hours for optimal results.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Reference range
Reference ranges vary by laboratory and reporting units. CD21+ B-lymphocytes typically represent 5-15% of total lymphocytes or 60-130 cells/μL in peripheral blood. Consult laboratory-specific reference range for specimen-based results.N/A
No special patient preparation required. Specimen type and source determine pre-analytical requirements; for blood specimens, collect in anticoagulant tube (EDTA or heparin) for flow cytometry.
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy