Overview: CD103 Test
Introduction: The CD103 Test measures CD103 expression on immune cells to diagnose conditions like hairy cell leukemia or autoimmune diseases, helping assess immune system function. Affecting 1 in 100,000 people annually, hairy cell leukemia poses diagnostic challenges due to its rarity. Following 2023 American Society of Hematology (ASH) guidelines, it uses flow cytometry for high accuracy, supporting hematology screening. This test is essential for diagnosis, treatment planning, and improving outcomes in hematology.

Other Names: CD103 Expression Test, Integrin Alpha E 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 Schlossman, who identified CD103 in leukemia. Flow cytometry advancements in the 2000s by BD Biosciences improved detection, surpassing earlier immunohistochemistry methods.

Purpose: Measures CD103 expression to diagnose hairy cell leukemia, guides therapy, and evaluates patients with fatigue, aiming to improve survival.

Test Parameters: CD103 expression

Pretest Condition: No special preparation required. Collect whole blood or tissue biopsy. Report history of immune issues.

Specimen: Whole Blood (EDTA, 2-5 mL), Tissue Biopsy (FFPE, 0.5-2 cma³); 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 fatigue or swollen lymph nodes. Include current medications or cancer history.

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

Procedural Considerations: Uses flow cytometry to measure CD103, 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: Positive CD103 confirms hairy cell leukemia, guiding therapy. Early treatment might improve survival, while untreated cases lead to death. Normal levels may require additional markers.

Specialist Consultation: Consult a hematologist for interpretation.

Additional Supporting Tests: Bone marrow biopsy, TRAP stain, or CD25 test to confirm diagnosis.

Test Limitations: Specific to CD103; correlation with other markers needed. False negatives possible with sample issues.

References: ASH Guidelines, 2023; Blood, Schlossman SF, 2022.