VWF Antigen Level Test - Von Willebrand Factor (VWF) Antigen Test

A quantitative immunoassay measures the concentration (amount) of von Willebrand factor (VWF) protein in blood plasma, usually using enzyme-linked immunosorbent assay (ELISA) or immunohistochemistry. The assay measures the protein's antigen level regardless of its function. It is used in conjunction with VWF activity assay (VWF:RCo) to diagnose and classify von Willebrand disease (VWD) by calculating the activity-to-antigen ratio.