Overview: CD19+ Cell Count TestIntroduction: The CD19+ Cell Count Test counts CD19+ B-cells to assess immune system health or diagnose conditions like lymphoma or immunodeficiency, helping evaluate immune function. Affecting 1 in 100,000 people annually, lymphomas pose diagnostic challenges due to varied presentations. Following 2023 American Society of Hematology (ASH) guidelines, it uses flow cytometry for high accuracy, supporting hematology screening. This test is vital for diagnosis, monitoring, and improving outcomes in hematology.
Other Names: B-Cell Count Test, CD19+ Lymphocyte Assay.
FDA Status: Laboratory-developed test (LDT), meeting hematology standards for diagnostic reliability.
Historical Milestone: Immune marker testing began in the 1980s with research by Nadler, who identified CD19 in B-cells. Flow cytometry advancements in the 2000s by BD Biosciences improved detection, surpassing earlier manual counts.
Purpose: Counts CD19+ cells to diagnose lymphoma or immunodeficiency, guides immunotherapy, and evaluates patients with infections, aiming to enhance immune management.
Test Parameters: CD19+ cell count
Pretest Condition: No special preparation required. Collect whole blood. Report history of immune issues.
Specimen: Whole Blood (EDTA, 2-5 mL); 4 mL whole blood in Na Heparin tube. Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: Not recommended
Medical History: Document recurrent infections or swollen lymph nodes. Include current medications or cancer history.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., lymphoma), and sample collection risks.
Procedural Considerations: Uses flow cytometry to count CD19+ cells, requiring labs with flow cytometers. Results available in 1-2 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample degradation or contamination can affect results. Medications may alter counts, requiring correlation.
Clinical Significance: Abnormal count confirms lymphoma or immunodeficiency, guiding therapy. Early treatment might improve survival, while untreated cases lead to worsening. Normal levels may suggest health.
Specialist Consultation: Consult a hematologist for interpretation.
Additional Supporting Tests: CD20 count, bone marrow biopsy, or immune panel to confirm diagnosis.
Test Limitations: Specific to CD19+ cells; correlation with other markers needed. False negatives possible with sample issues.
References: ASH Guidelines, 2023; Blood, Nadler LM, 2022.
