Overview: Protein C Antigen TestIntroduction: The Protein C Antigen Test measures Protein C to diagnose clotting disorders, causing thrombosis. Aligned with 2023 ISTH guidelines, it uses immunoassays for high specificity, supporting coagulation screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in immunology for patients with suspected Protein C deficiency or thrombophilia.
Other Names: Protein C Antigen Assay, Coagulation Protein Test.
FDA Status: Laboratory-developed test (LDT), meeting immunology standards for diagnostic accuracy.
Historical Milestone: Protein C testing began in the 1980s with thrombophilia research. Immunoassay methods improved in the 2000s, enhancing diagnostic precision.
Purpose: Measures Protein C to diagnose clotting disorders, guides treatment, and evaluates patients with thrombosis.
Test Parameters: 1. Protein C Antigen Level
Pretest Condition: No fasting required. Collect serum or plasma. Report history of thrombosis or clotting disorders.
Specimen: Serum (SST, 2-5 mL), Plasma (NaCit, 2-4 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document thrombosis, family history of clotting disorders, or cardiovascular events. Include current medications, especially anticoagulants.
Consent: Written consent required, detailing the tests purpose, clotting disorder implications, and risks of sample collection.
Procedural Considerations: Uses enzyme-linked immunosorbent assay (ELISA) to measure Protein C antigen levels. Results are available in 1-2 days, supporting clinical decisions. Performed in laboratories, often for clotting disorder diagnosis.
Factors Affecting Result Accuracy: Sample hemolysis or improper storage can affect results. Anticoagulants may lower Protein C levels.
Clinical Significance: Low Protein C confirms deficiency, guiding anticoagulant therapy. Normal levels may require functional testing.
Specialist Consultation: Consult a hematologist for result interpretation and treatment planning.
Additional Supporting Tests: Protein C functional test, D-dimer, or genetic testing to confirm clotting disorder diagnosis.
Test Limitations: Non-specific for certain clotting disorders; clinical correlation is needed. Sample quality affects sensitivity.
References: ISTH Thrombophilia Guidelines, 2023; Journal of Thrombosis and Haemostasis, Bertina RM, 2022.
