###1: CD19-Positive Kappa Light Chain-Expressing Cells in Whole Blood
###3: This test measures CD19-positive cells in the blood that express the kappa type of immunoglobulin light chain. CD19 is found on B lymphocytes, and kappa light chains are one of two light-chain types produced by B cells.
["###4: The result helps evaluate the number and distribution of a specific group of B cells, but it must be interpreted with other laboratory and clinical findings."]
Key facts at a glance
- LOINC
- 50664-2
- Short code
- CD19KAPC
- Synonyms
- CD19+Kappa+ Cells # Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender/purple-top) tube for flow cytometry; sodium heparin (green-top) tube acceptable for some platforms
- Units
- N/A
- Ref low
- 80
- Ref high
- 500
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Flow cytometry using fluorochrome-conjugated antibodies against CD19 and surface immunoglobulin kappa light chain, with absolute count calculated using counting beads or dual-platform methodology (CD45+ lymphocyte gating plus white blood cell count)
- CPT
- 86356 (single marker flow cytometry, per marker); may include 88184-88189 for flow cytometry interpretation and gating
- SNOMED
- 405484003 (B lymphocyte count) and 116647005 (Kappa light chain measurement)
- Specimen volume
- 3-5 mL whole blood for adults; minimum 1 mL for pediatric patients. Maintain anticoagulant-to-blood ratio per tube manufacturer specifications
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-22°C). Refrigeration (2-8°C) may extend viability up to 72 hours for some markers but may affect surface immunoglobulin expression. Do not freeze. Optimal analysis within 24 hours of collection.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
###5: What this test measures
###6: The test identifies blood cells that carry both the CD19 marker and the kappa light-chain marker. CD19 is associated with B lymphocytes, while the kappa marker distinguishes B cells that make one type of immunoglobulin light chain from those that make the other type, called lambda.
###7: How the test is performed
###8: A whole-blood sample is collected, usually by drawing blood from a vein. The laboratory analyzes the cells to determine how many express CD19 and kappa together. The sample may be evaluated as part of a broader blood-cell immunophenotyping panel.
###9: How to understand the result
###10: The report may provide a count or proportion of CD19-positive kappa cells. A result outside the laboratory's expected range can reflect a change in the number of B cells or a predominance of kappa-producing cells, but factors such as infection, medication use, and sample handling can also affect the result.
###11: Why the test may be ordered
###12: Clinicians may order this test when investigating an unusual B-cell count, suspected blood-cell disorders, or findings that could be associated with a lymphoproliferative condition. It is often interpreted alongside the complete blood count, symptoms, and other immune-cell tests.
Reference range
CD19+ Kappa+ B cells absolute count in peripheral blood. Reference ranges vary by laboratory; commonly reported as approximately 80-500 cells/μL (0.08-0.50 x 10^9/L) in healthy adults. Kappa:Lambda ratio among B cells typically 0.8-2.0 (normal B-cell clonality assessment)N/A
No fasting required. Patient should be well-hydrated. Recent corticosteroid therapy, chemotherapy, immunosuppressive medications, or rituximab treatment may significantly affect B-cell counts. Provide complete clinical history including medication list and clinical indication for testing (e.g., suspected immunodeficiency, B-cell lymphoproliferative disorder, autoimmune disease monitoring). Specimen should be collected before initiating immunosuppressive therapy when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
###2: Blood CD19-positive kappa-cell count
Frequently asked questions
###14: Does a high or low result mean I have cancer?
###16: What is the difference between kappa and lambda cells?
###18: Can medications or a recent illness affect the result?
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