Overview: CD16 Test
Introduction: The CD16 Test tests CD16 expression on immune cells to diagnose immune disorders or monitor infections, helping evaluate immune system function and infection response. Affecting 1 in 1,000 immunocompromised individuals 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: FcγRIII Test, CD16 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 Perussia, who identified CD16 in NK cells. Flow cytometry advancements in the 2000s by BD Biosciences improved detection, surpassing earlier ELISA methods.

Purpose: Measures CD16 expression to assess immune disorders, guides immunotherapy, and evaluates patients with infections, aiming to enhance immune response.

Test Parameters: CD16 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 immune issues. Include current medications or treatment history.

Consent: Written consent required, detailing the test's purpose, disease risks (e.g., sepsis), and sample collection risks.

Procedural Considerations: Uses flow cytometry to measure CD16, 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 CD16 indicates immune dysfunction, guiding therapy. Early intervention might prevent complications, while untreated cases lead to worsening. Normal levels may suggest recovery.

Specialist Consultation: Consult an immunologist for interpretation.

Additional Supporting Tests: CD56 count, immune panel, or infection markers to confirm diagnosis.

Test Limitations: Specific to CD16; correlation with other markers needed. False negatives possible with sample issues.

References: SITC Guidelines, 2023; Journal of Immunology, Perussia B, 2022.