B-cell Lymphocyte Count (Absolute)
This test measures the number of B cells, a type of white blood cell involved in immune response and antibody production.
["B-cell counts help assess immune function and detect conditions affecting B cells."]
Key facts at a glance
- LOINC
- 32524-1
- Short code
- CD19BM
- Synonyms
- CD19 Cells # Mar
- Category
- chemistry
- Sample
- serum
- Container
- Heparinized bone marrow aspirate collected in sodium heparin or EDTA tube for flow cytometry; sterile collection container acceptable for direct transport to flow cytometry laboratory
- Units
- N/A
- Ref low
- 2
- Ref high
- 20
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Flow cytometry using fluorescently labeled monoclonal antibodies against CD19 surface marker; cells analyzed on a bone marrow aspirate sample
- CPT
- 86356
- SNOMED
- 1428001000000101
- Specimen volume
- 1-3 mL of bone marrow aspirate; first-pull aspirate preferred for accurate representation of marrow cellularity
- Stability
- Specimen must be processed within 24 hours of collection when stored at room temperature (18-25°C); up to 48 hours if stored at 2-8°C; viability decreases significantly beyond these timeframes
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What Is a B-Cell Count Test Used For?
A B-cell count test is often ordered to evaluate immune health, diagnose or monitor conditions like chronic lymphocytic leukemia, autoimmune diseases, or infections that may deplete B cells. It may also be used before or after treatments that affect the immune system, such as chemotherapy or certain medications.
When Might You Need This Test?
Your doctor may recommend a B-cell count if you have symptoms like frequent infections, unexplained fatigue, swollen lymph nodes, or if you’re undergoing treatment that could impact your immune cells. It’s also part of routine monitoring for certain blood disorders or immune-related conditions.
How Is the Test Performed?
A small sample of blood is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the number of B cells present in your circulation.
What Do Results Mean?
Results show the absolute number of B cells per microliter of blood. Low counts may indicate immune deficiencies or certain cancers, while very high counts could suggest overactive immune responses or other conditions.
Reference range
Reference ranges for CD19+ B-lymphocytes in bone marrow vary by laboratory and age. Typical reported values range from 2-20% of total nucleated cells or absolute counts provided as cells/µL. Pediatric and adult ranges differ; consult laboratory-specific reference interval.N/A
No special patient preparation required. Inform physician of any recent immunotherapy, rituximab or other anti-CD20 therapy, corticosteroid use, or recent transfusion history as these may affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
B-Cell Count
Frequently asked questions
Why might my B-cell count be checked regularly during treatment for a blood-related condition?
Can diet or lifestyle factors affect my B-cell count?
What if my B-cell count is outside the expected range?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy