Von Willebrand Factor Antigen
Von Willebrand factor (VWF) antigen is a test that measures the amount of von Willebrand factor, a protein that helps platelets stick together and supports clotting. It also helps carry another clotting factor in the blood.
VWF is important for the early steps of forming a clot, so measuring it helps evaluate certain bleeding tendencies. The antigen test is often part of a workup for von Willebrand disease or unexplained bleeding. It is typically interpreted alongside related clotting-factor tests.
A high VWF level can occur with inflammation, stress, pregnancy, or infection, since it behaves as an acute-phase protein. Elevated levels are usually interpreted cautiously and in context. Your clinician will consider the reason for testing when reviewing the result.
A low VWF level can contribute to a tendency to bleed or bruise more easily and is a key finding in von Willebrand disease. Your clinician will use additional tests to interpret a low result.
A value within the normal range supports typical clotting function. Because levels are influenced by factors like blood type and inflammation, your clinician will interpret your result in context.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.