CD19

Immunity

Report in 72Hrs

At Home

No Fasting Required

Details

Flow cytometry panel of immune cell surface markers.

₹2,738₹3,911

30% OFF

CD19 Test Information Guide

Why is it done?
- CD19 is a flow cytometry marker used to identify and enumerate B lymphocytes in blood and other body tissues. It measures the presence and quantity of B cells expressing the CD19 antigen on their surface.
- Primary Indications: Diagnosis and monitoring of B-cell malignancies (chronic lymphocytic leukemia, B-cell lymphomas); Evaluation of immunodeficiency disorders; Assessment of immune reconstitution post-transplantation; Monitoring B-cell recovery after chemotherapy or immunosuppressive therapy; Investigation of recurrent infections suggesting B-cell dysfunction; Baseline assessment before CAR-T cell therapy; Evaluation of autoimmune conditions involving B-cell abnormalities.
- Typical Timing: Performed when lymphoproliferative disorders are suspected; During initial diagnosis workup; Periodically during chemotherapy treatment; After hematopoietic stem cell or solid organ transplantation; When monitoring response to immunosuppressive or targeted therapies.
Normal Range
- Reference Range (Adults): CD19+ B cells typically comprise 5-15% of total lymphocytes; Absolute count: 100-600 cells/μL (0.1-0.6 × 10⁹/L) in peripheral blood.
- Reference Range (Children): Varies by age; Infants/toddlers (0-2 years): 2000-8000 cells/μL; Young children (2-6 years): 1000-4500 cells/μL; Older children (6-12 years): 500-2000 cells/μL; Adolescents approach adult values.
- Units of Measurement: Cells/μL (cells per microliter); × 10⁹/L (cells per liter); Percentage of total lymphocytes.
- Interpretation of Results: Normal: CD19+ B cell count within age-appropriate reference range, indicating adequate B-cell population; Elevated: Increased CD19+ cells suggesting B-cell proliferation, lymphocytosis, or malignancy; Decreased/Absent: Low or absent CD19+ cells indicating B-cell immunodeficiency, B-cell aplasia, or effect of B-cell-depleting therapies; Borderline: Values near upper or lower limits may require clinical correlation and repeat testing.
Interpretation
- Elevated CD19+ B Cell Counts: May indicate chronic lymphocytic leukemia (CLL), other B-cell lymphomas, reactive lymphocytosis from infection or inflammation, or post-vaccination B-cell response. Marked elevation with abnormal B-cell populations suggests hematologic malignancy requiring further investigation.
- Decreased/Absent CD19+ B Cells: Indicates B-cell deficiency seen in X-linked agammaglobulinemia, common variable immunodeficiency, acute leukemia with B-cell involvement, or therapeutic B-cell depletion (anti-CD19 or anti-CD20 therapy). Low counts impair humoral immunity and antibody production.
- Clinical Significance of Result Patterns: Isolated B-cell reduction with normal T cells: Primary B-cell defect; Combined reduction of B and T cells: Severe immunodeficiency (SCID, DiGeorge); Abnormal B-cell populations on flow cytometry: Suggestive of malignancy; Serial decrease post-therapy: Good response to B-cell-targeted treatment; Serial increase post-transplant: Successful immune reconstitution.
- Factors Affecting Results: Recent vaccination or infection; Immunosuppressive medications; Chemotherapy exposure; Age (pediatric values differ); Time of sample collection (diurnal variation); Recent transfusion; Splenectomy or splenic dysfunction; Bone marrow disorders; Timing relative to therapeutic B-cell depletion.
Associated Organs
- Primary Organ Systems Involved: Lymphoid system (bone marrow, lymph nodes, spleen, thymus); Hematopoietic system (blood and blood-forming organs); Immune system (central and peripheral lymphoid tissues).
- Medical Conditions Associated with Abnormal Results: Malignancies: Chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, marginal zone lymphoma, Hodgkin lymphoma (indirect involvement); Immunodeficiencies: X-linked agammaglobulinemia, common variable immunodeficiency (CVID), selective IgA deficiency, DiGeorge syndrome, SCID; Autoimmune Disorders: Systemic lupus erythematosus, rheumatoid arthritis, primary Sjögren's syndrome; Other Conditions: HIV infection, active tuberculosis, chronic infections, post-transplant lymphoproliferative disorder (PTLD).
- Potential Complications of Abnormal Results: High counts: Progressive leukemia/lymphoma; Leukostasis; Tumor lysis syndrome with treatment initiation; Complications of underlying malignancy. Low counts: Recurrent infections; Sepsis and severe infection; Autoimmune complications; Poor vaccination response; Increased malignancy risk (in primary immunodeficiency).
Follow-up Tests
- Recommended Follow-up Testing Based on Results: Complete Flow Cytometry Panel: CD3, CD4, CD8, CD16, CD56 for comprehensive lymphocyte subset analysis; CD19 subsets analysis: CD19+CD5+, CD19+CD23+ patterns; B-cell clonality studies: To assess for monoclonal vs. polyclonal B-cell populations.
- Further Investigations if Malignancy Suspected: Bone marrow biopsy and aspiration; Immunoglobulin gene rearrangement studies (IgH, IgK, IgL); FISH/cytogenetics; LDH and Beta-2 microglobulin levels; Imaging studies (CT, PET scan) for lymphoma staging; B-cell receptor sequencing if indicated.
- Immunodeficiency Workup if B-cells Low: Immunoglobulin levels (IgG, IgA, IgM); Specific antibody responses (tetanus, pneumococcal); T-cell function tests (mitogen stimulation); Genetic testing if primary immunodeficiency suspected; Complement studies (C3, C4, total complement).
- Monitoring Frequency for Ongoing Conditions: CLL: Every 3-6 months initially, then based on progression; During chemotherapy: Every 1-2 cycles; Post-transplant: Weekly initially, then monthly, then quarterly; B-cell depletion therapy (rituximab, etc.): Monthly during therapy, then 3-6 months post-therapy; Immune reconstitution: Monthly post-transplant, then quarterly for first year.
- Related Complementary Tests: CD20 (pan-B cell marker); CD5 (subset identification in CLL); CD23 (distinguishes CLL from other B-cell neoplasms); CD10 (germinal center marker); Surface immunoglobulin (light chain restriction); BCL-2 and other prognostic markers; CD19 CAR-T cell monitoring for treatment efficacy.
Fasting Required?
- Fasting Required: No
- Special Instructions: No fasting period required; Patient may eat and drink normally; No specific dietary restrictions necessary.
- Medications: Continue all regular medications unless specifically instructed otherwise; Do not stop immunosuppressive or chemotherapy medications without consulting physician; Inform phlebotomist of current medications, especially B-cell depleting agents or recent transfusions.
- Patient Preparation Requirements: Provide informed consent for blood draw; Wear loose, comfortable sleeves for easy blood draw access; Remain seated for 5 minutes before phlebotomy to avoid syncope; Stay hydrated (drink water before test); Notify technician of any bleeding disorders or medication sensitivities; For pediatric patients: Parent/guardian should accompany child.
- Sample Collection: Peripheral blood draw into EDTA tube (purple-top); Minimum 2-3 mL of whole blood typically required; Sample must be processed within 24-48 hours for optimal results; Room temperature storage acceptable for flow cytometry samples; Avoid hemolysis during collection.

How our test process works!