What does it mean if von Willebrand antigen is high?
Increased concentrations of VWF antigen and VWF activity are not considered diagnostic. VWF is one of many acute phase reactants. This means that levels will be temporarily increased with infections, inflammation, trauma, and with physical and emotional stressors.
What is the normal range for von Willebrand factor antigen?
VWF antigen levels usually range from 50-200 IU/dL (50-200% of normal). Levels <50 IU/dL are considered low and are diagnostic of VWD in a patient with abnormal bleeding, James PD, Connell NT, Ameer B, et al.
What is the Ristocetin test used for?
Doctors order the vWF activity – ristocetin cofactor test (also called von Willebrand activity test or RCF activity test) to help diagnose or monitor the treatment of von Willebrand disease. Often, doctors do this test along with others to get a fuller picture of clotting ability.
What blood test is used for von Willebrand disease?
The blood tests that a doctor can order to diagnose VWD (or another platelet disorder) include: Factor VIII clotting activity―To measure the amount of factor VIII in the blood. Von Willebrand factor antigen―To measure the amount of VWF in the blood.
How do you classify von Willebrand disease?
VWD is classified into three primary categories. Type 1 includes partial quantitative deficiency, type 2 includes qualitative defects, and type 3 includes virtually complete deficiency of VWF. VWD type 2 is divided into four secondary categories.
What is a low von Willebrand factor?
Von Willebrand disease is a lifelong bleeding disorder in which your blood doesn’t clot properly. People with the disease have low levels of von Willebrand factor, a protein that helps blood clot, or the protein doesn’t perform as it should.
Why is PT normal in von Willebrand disease?
It measures primarily the clotting ability of factors I (1), II (2), V (5), VII (7), and X (10). If the level of any one of these factors is too low, it will take longer than normal for the blood to clot. The results of this test will be normal among most people with VWD.
What is the best test to diagnose von Willebrand’s disease?
Diagnostic Tests The blood tests that a doctor can order to diagnose VWD (or another platelet disorder) include: Factor VIII clotting activity―To measure the amount of factor VIII in the blood. Von Willebrand factor antigen―To measure the amount of VWF in the blood.
What is a von Willebrand factor antigen test?
A von Willebrand factor (vWF) antigen test measures the quantity of a protein called von Willebrand factor that helps blood to clot. A clot is a lump of blood that the body produces to prevent excessive bleeding by sealing leaks in blood vessels caused by wounds, cuts, scratches, and other conditions.
What is the half life of von Willebrand factor?
Description. von Willebrand factor (vWF) is multimeric protein (molecular weight varies from 500-20,000 kd) that is assembled from identical monomers in endothelial cells and megakaryocytes and can be released from endothelium and platelets upon activation. The half-life of vWF is approximately 12 hours (range, 9-15 h),…
What percentage of von Willebrand disease is normal?
A person with 20% to 40% of the normal amount of vWF would likely have a mild form of von Willebrand disease. A person with less than 10% would have a more severe form. The vWF antigen test is considered a safe procedure.
Why would a doctor order the vWF antigen test?
Doctors order the vWF antigen test to help diagnose or monitor the treatment of von Willebrand disease. Symptoms of von Willebrand disease can include easy bruising, frequent nosebleeds, excessive bleeding after a mouth injury or dental work, abnormal menstrual bleeding, or, in infant boys, prolonged bleeding after circumcision.