Overview: CD45RA TestIntroduction: The CD45RA Test measures CD45RA expression to assess immune cell types, helping diagnose immune disorders or monitor infections like HIV, aiding in treatment planning. Affecting 1 in 1,000 HIV patients annually, immune dysfunction poses diagnostic challenges. Following 2023 International Society for Immunotherapy of Cancer (SITC) guidelines, it uses flow cytometry for high accuracy, supporting hematology screening. This test is vital for diagnosis, monitoring, and improving outcomes in immunology.
Other Names: Naive T-Cell Marker Test, CD45RA Expression 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 Thomas, who linked CD45RA to naive T-cells. Flow cytometry advancements in the 2000s by BD Biosciences improved detection, surpassing earlier ELISA methods.
Purpose: Measures CD45RA expression to assess immune disorders, guides immunotherapy, and evaluates patients with infections, aiming to enhance immune management.
Test Parameters: CD45RA expression
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 HIV history. Include current medications or treatment history.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., AIDS), and sample collection risks.
Procedural Considerations: Uses flow cytometry to measure CD45RA, 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 expression, requiring correlation.
Clinical Significance: Abnormal CD45RA indicates immune dysfunction, guiding therapy. Early intervention might prevent progression, while untreated cases lead to worsening. Normal levels may suggest health.
Specialist Consultation: Consult an immunologist for interpretation.
Additional Supporting Tests: CD45RO count, immune panel, or viral load to confirm diagnosis.
Test Limitations: Specific to CD45RA; correlation with other markers needed. False negatives possible with sample issues.
References: SITC Guidelines, 2023; Journal of Immunology, Thomas ML, 2022.
