The von Willebrand Factor (vWF) is a protein that promotes platelet-to-platelet and platelet-to-vessel interaction during the coagulation process. Genetic defects on the vWF that will impair its synthesis or function often may result in bleeding disorders called von Willebrand Disease (vWD). Von Willebrand Disease is the most common hereditary bleeding disorder, occurring in up to 1% of the general population. Initial tests for vWD are bleeding time, platelet count and aPTT. In vWD, the platelet count and platelet morphology are generally normal. Bleeding time is usually prolonged (markedly prolonged by aspirin). Diagnosis of vWD is suggested by bleeding symptoms and family history. These tests are then followed by diagnostic tests such as vWF antigen and activity. Further tests may be necessary to distinguish the subtypes of vWD, such as vWF multimer analysis, factor VIII assay, and platelet aggregation studies (low-dose ristocetin).
vWF Factor Antigen testing is also used to differentiate between von Willebrand’s Disease and Hemophilia A, to help determine Hemophilia A carrier status, and to differentiate other bleeding disorders.
vWF Factor Antigen testing is performed on a blood sample drawn from a vein in the patient’s arm. Additional tests may include Bleeding time, Prothrombin Time, Partial Thromboplastin Time, Factor VIII, and Platelet count.
Reference ranges and specimen collection vary from test method and laboratories performing this test. To properly evaluate your test results, consult with the ordering physician or healthcare provider. If you would like to learn more about testing for von Willebrand Factor Protein click here for further information or you can research one of the references listed below.
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