{"id":"protein-c-activity","name":"Protein C Activity","shortName":"Protein C","aliases":["Protein C, Functional","Protein C","Protein C Chromogenic","Protein C Activity, Chromogenic","Protein C Activity Assay","Protein C Functional","Functional Protein C","Protein C Activity, P","Protein C Activity, Plasma","Protein C, Functional, Plasma","PROT C F"],"abbreviations":["PC","Protein C"],"loinc":[{"code":"27818-4","primary":true},{"code":"27819-2","primary":false},{"code":"6006-1","primary":false}],"specimen":"plasma","units":[{"ucum":"%","display":"%"},{"ucum":"[IU]/dL","display":"IU/dL"}],"referenceRanges":[{"population":"18+","low":65,"high":150,"unit":"%","unitDisplay":"%","note":"University of Washington (UW Medicine) interval for ages 10 and over, both sexes, using a chromogenic method. Protein C intervals depend on the method and the reference group, and labs differ: ARUP Laboratories (clot-based method) lists 83–168% for adults, Indiana University Health lists 74–145%, and a UK haemostasis reference puts adult levels at about 65–135 IU/dL. Mayo Clinic Laboratories' thrombophilia profile follows up a protein C activity under 70% with an antigen test when no acquired cause is found. Use the range printed on your own report.","sources":[{"title":"Protein C Activity (test code PCCLOT)","url":"https://dlmp.uw.edu/test-guide/view/PCCLOT","publisher":"UW Medicine, Department of Laboratory Medicine and Pathology"},{"title":"Thrombosis & Hemostasis Reference Ranges (updated 1/11/2021)","url":"https://cdn.iuhealth.org/resources/Thrombosis-Hemostasis-Ref-Ranges-No-StarMax.pdf","publisher":"Indiana University Health Pathology Laboratory","year":2021},{"title":"Protein C Assays","url":"https://www.practical-haemostasis.com/Thromobophilia/pc_assays.html","publisher":"Practical-Haemostasis.com"},{"title":"Protein C, Functional (test 0030113)","url":"https://ltd.aruplab.com/Tests/Pub/0030113","publisher":"ARUP Laboratories"},{"title":"Thrombophilia Profile, Plasma and Whole Blood (test ID AATHR)","url":"https://www.testcatalog.org/show/AATHR","publisher":"Mayo Clinic Laboratories (Extended Catalog, via testcatalog.org)"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures how well protein C works. Protein C is a natural blood thinner made in the liver that helps keep your blood from clotting too easily.","url":"https://bloodtesttracker.com/markers/protein-c-activity","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}