CD19+ B-Cell Count in Peripheral Blood (Absolute Count)
This test measures the number of CD19+ cells, a type of immune cell (B-cell) found in your blood. It helps assess immune function, particularly in conditions affecting B-cells.
["This test helps evaluate your immune system’s B-cell activity, useful in diagnosing or monitoring certain blood disorders."]
Key facts at a glance
- LOINC
- 57432-7
- Short code
- CD19KAPPA
- Synonyms
- CD19+Kappa+ Cells NFr Fld
- Category
- chemistry
- Sample
- serum
- Container
- Sterile body fluid collection container; lavender-top (EDTA) tube for anticoagulated samples; sterile conical tube for serous fluids
- Units
- N/A
- Ref low
- 1
- Ref high
- 2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Flow Cytometry with immunofluorescence staining using anti-CD19 and anti-kappa light chain monoclonal antibodies
- CPT
- 86356
- SNOMED
- 394770006
- Specimen volume
- Minimum 5 mL of body fluid; 10 mL preferred for adequate cell yield. For cerebrospinal fluid, minimum 1-3 mL depending on cell count.
- Stability
- Specimen should be processed within 4-6 hours of collection for optimal viability. If delayed, store at 2-8°C and process within 24 hours. Do not freeze.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
What Is CD19+ B-Cell Count Measuring?
CD19 is a protein found on the surface of most B-cells, which are a key part of the immune system. This test counts these cells in a blood sample to determine their presence and quantity. It’s often used to monitor immune health, especially in conditions like chronic lymphocytic leukemia (CLL) or other B-cell-related disorders.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms or conditions linked to abnormal B-cell activity, such as infections, autoimmune diseases, or blood cancers. It can also help track treatment responses in certain immune-related conditions.
How Is the Test Performed?
A small blood sample is drawn from a vein, typically in your arm. The sample is then analyzed in a lab to count the CD19+ cells. No special preparation is usually needed, but fasting may be advised depending on the clinical context.
What Do Results Mean?
Results provide the absolute number of CD19+ B-cells per microliter of blood. Abnormal counts may indicate immune dysfunction, infection, or a blood disorder. Your results will be interpreted by your healthcare provider in the context of your overall health and symptoms.
Reference range
CD19+ B cells with kappa light chain restriction are evaluated as a percentage of total lymphocytes or as absolute count. Reference ranges vary by laboratory; typically, kappa-restricted B-cell populations represent the majority of CD19+ cells in normal polyclonal populations. Kappa:Lambda ratio in normal peripheral blood B cells is approximately 1.0-2.0.N/A
No fasting required. Patient should be well-hydrated. Recent blood transfusions, immunosuppressive therapy, or vaccination may affect lymphocyte subset counts. Inform laboratory of any recent immunomodulatory treatments.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CD19+ B-cell counts may suggest conditions like chronic lymphocytic leukemia (CLL), immune deficiencies, or reactive B-cell proliferation. Low counts could indicate immune suppression or certain autoimmune diseases. This test is critical for diagnosing, monitoring, and guiding treatment for B-cell-related disorders.
Short name
CD19+ B-Cell Count
Frequently asked questions
How often will I need this test?
What are the possible risks or side effects of this test?
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