What is normal range of VWF?

In the general population, the mean level of plasma VWF is 100 IU per dL, with a normal reference range between 50 and 200 IU per dL. The 5 percent of persons with VWF levels of less than 50 IU per dL include those with VWD and those with slightly low, but nondiagnostic, levels.

What is VWF Antigen?

VWF antigen – this test measures the amount of the VWF protein present in the blood. VWF activity (also called Ristocetin Cofactor) – this test determines whether the protein is functioning properly.

What causes high VWF?

VWF is an acute-phase reactant and may be elevated above baseline in association with a variety of conditions including inflammation, stress, exercise, liver disease, pregnancy or estrogen therapy. Baseline VWF levels also increase with aging.

What does low VWF mean?

A sufficiently low level of von Willebrand factor (VWF) predisposes to bleeding that can be quite serious, and low VWF is a diagnostic feature of von Willebrand disease (VWD) type 1, which is characterized by partial quantitative deficiency of VWF.

Why is PT normal in von Willebrand disease?

PT and aPTT The prolongation is secondary to low levels of FVIII because one of the normal functions of vWF is to protect FVIII from degradation. The PT should be within reference ranges.

What does a high factor 8 level mean?

If your levels of factor VIII are too high, you are likely at a higher risk for thrombosis, which is blood clot formation in your blood vessels. In this case, your doctor may perform additional tests or prescribe anticoagulant therapy.

What is the function of VWF?

Von Willebrand factor (VWF) is a large multimeric glycoprotein that performs two critical functions in primary hemostasis: it acts as a bridging molecule at sites of vascular injury for normal platelet adhesion, and under high shear conditions, it promotes platelet aggregation.

What is VWF in blood?

Von Willebrand disease (VWD) is a blood disorder in which the blood does not clot properly. Blood contains many proteins that help the blood clot when needed. One of these proteins is called von Willebrand factor (VWF).

What causes low VWF?

VWF can be low because there is a problem with how it is made and released from cells or may be related to blood type. Though there is less VWF (low), VWF works like it is supposed to. Low VWF isn’t always genetic (passed down from parent to child through information in the cells called the VWF gene)

How is low von Willebrand disease treated?

Treatment options for patients with low VWF and significant bleeding phenotypes include antifibrinolytic agents, such as tranexamic acid or aminocaproic acid, DDAVP, and VWF-containing concentrates. Tranexamic acid has been widely used in the management and prevention of bleeding in VWD.

What is the average vWF level for a blood type?

50% to 150%. Average vWF levels (both antigen and activity) tend to vary by blood type. 6 One study found the mean vWF levels by blood type to be as follows: 7 See von Willebrand Factor (vWF) Profile [084715] for more clinical information.

What is normal blood group von Willebrand factor antigen?

Note: Individuals of blood group “O” may have lower plasma von Willebrand factor (VWF) antigen than those of other ABO blood groups, such that apparently normal individuals of blood group “O” may have plasma VWF antigen as low as 40% to 50%, whereas the lower limit of the reference range for individuals of other blood groups may be 60% to 70%.

What happens if the vWF antigen test is normal?

If the VWF antigen test is normal or nearly normal and the VWF activity (Ristocetin Cofactor) is decreased, then the person may have Type 2 VWD. Further testing (e.g., VWF multimeric analysis) will be required to determine which subtype is present.

Where can I find reference ranges for VWF assays?

Hi, Charlie. the typical reference ranges for VWF assays are: These are taken from Marques MB, Fritsma GA. Quick Guide to Coagulation Testing, 2nd Edition, 2009, AACC Press, and will vary slightly by locale and institution. Your local laboratory manual should provide the ranges for your institution.