Von Willebrand Disease is caused by low levels of functional von Willebrand factor. Von Willebrand factor has two main functions: 1) connecting platelets to sites of injured blood vessels and 2) protecting factor VIII from a normal breakdown in the blood circulation. There are at least 6 types of von Willebrand Disease.
Platelet function disorders are a collection of disorders that leads platelets to not function properly. Platelets are cells that are in circulation and can be thought of as the first responder to injury. When a blood vessel is damaged, the platelets quickly get stuck at that injured site and form a plug to stop the bleeding. Patients with platelet function defects typically have normal platelet counts, but each platelet doesn’t work as well as it should. Testing for a platelet function disorder can include testing how the platelets clump together (platelet aggregation), how the proteins in the platelet are released when platelets are activated (platelet release assay), measuring the markers (receptors) on the outside of the platelets, and using electron microscopy to exam the platelet contents.
