{"id":"vwf-antigen","name":"von Willebrand Factor Antigen (VWF:Ag)","shortName":"VWF Antigen","aliases":["VWF:Ag","von Willebrand Factor Antigen","vWF Antigen","von Willebrand Antigen","Factor VIII Related Antigen","VWF Antigen, Plasma","von Willebrand Factor Antigen, Plasma","von Willebrand Factor Ag, P","von Willebrand Factor, Antigen","VWF/AG","vWF Ag","von Willebrand Ag"],"abbreviations":["VWF:Ag","vWF Ag","VWF Ag"],"loinc":[{"code":"27816-8","primary":true},{"code":"6012-9","primary":false},{"code":"41867-3","primary":false}],"specimen":"plasma","units":[{"ucum":"%","display":"%"},{"ucum":"[IU]/dL","display":"IU/dL"},{"ucum":"[IU]/mL","display":"IU/mL"}],"referenceRanges":[{"population":"18+","low":52,"high":214,"unit":"%","unitDisplay":"%","note":"ARUP Laboratories interval for ages 18 and over, both sexes (microlatex immunoassay). Other labs differ: Mayo Clinic Laboratories lists 55–200%, UW Medicine lists 50–200%, and Indiana University Health lists 44–167%. People with blood group O often have lower VWF. Mayo notes that apparently healthy people in group O can have antigen as low as 40% to 50%, while the lower limit for other blood groups may be 60% to 70%. The 2021 ASH/ISTH/NHF/WFH guideline says ABO-specific ranges are not required and that the lab's own lower limit should be used if it is below 50%. Use the range printed on your own report.","sources":[{"title":"von Willebrand Factor Antigen (test 0030285)","url":"https://ltd.aruplab.com/Tests/Pub/0030285","publisher":"ARUP Laboratories"},{"title":"von Willebrand Disease Profile, Plasma (test ID AVWPR)","url":"https://www.testcatalog.org/show/AVWPR","publisher":"Mayo Clinic Laboratories (Extended Catalog, via testcatalog.org)"},{"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":"ASH ISTH NHF WFH 2021 guidelines on the diagnosis of von Willebrand disease","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC7805340/","publisher":"Blood Advances","year":2021},{"title":"Von Willebrand Factor Antigen (test code VWFAG)","url":"https://dlmp.uw.edu/test-guide/view/VWFAG","publisher":"UW Medicine, Department of Laboratory Medicine and Pathology"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"Measures how much von Willebrand factor is in your blood. It is usually ordered with VWF activity and factor VIII to look into von Willebrand disease.","url":"https://bloodtesttracker.com/markers/vwf-antigen","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}