Von Willebrand Factor
Von Willebrand factor (vWF or VWF) is a protein that is one of several components of the coagulation system that work together, and in sequence, to stop bleeding within the body. VWF testing measures the amount of the protein present in blood and determines how well the protein functions. Von Willebrand disease is the most common hereditary bleeding disorder that is caused by a deficiency of von Willebrand factor. Von Willebrand factor helps blood platelets clump together and stick to the blood vessel wall, which is necessary for normal blood clotting.