How is VWD diagnosed?
VWD can be difficult to diagnose and repeated testing may be needed to confirm the diagnosis.
Many people’s symptoms are mild and they may not be diagnosed until they have a major bleeding problem, eg from surgery or an injury. However, if they have a severe form of VWD, they will usually have major bleeding problems as a baby or small child and will often be diagnosed within their first year of life.
Diagnosing VWD involves:
- A personal history of bleeding or bruising more than normal from mucous membranes or skin after injury, trauma or surgery and
- A family history of bleeding more than normal and
- Specialised laboratory test results for VWD
Tests for VWD
The doctor may order several laboratory tests on blood samples:
- Von Willebrand factor antigen: to measure the amount of von Willebrand factor in your blood
- Von Willebrand factor ristocetin cofactor activity and/or the collagen binding assay: to show how well the von Willebrand factor works
- Factor VIII clotting activity: to measure how well the von Willebrand factor binds to the factor VIII protein and maintains the level of factor VIII in the blood. Some people with VWD have low levels of factor VIII, while others have normal levels
- Von Willebrand factor multimers: if some tests suggest you have VWD, this test is used to show the makeup or structure of the von Willebrand factor and helps to diagnose the type of VWD
- Platelet function test: to measure how well your platelets are working.
Understanding the laboratory test results is complex and needs to be done by a haematologist (specialist doctor) and laboratory with experience in VWD.
VWD can only be diagnosed with specialised blood tests. Routine blood tests often give normal results, which is why the person’s history of bleeding is so important. Testing is often repeated because a person’s VWF and factor VIII levels can vary at different times. For example, several common experiences can cause the level of VWF to rise in the blood and appear to be normal:
- Normal hormonal changes during a woman’s monthly menstrual cycle
- Hormone treatment.
Inflammation with other health problems or blood type can also affect levels of VWF and factor VIII in the blood. People with type O blood often have lower levels of VWF.
If you think you have a bleeding problem, it is important to see a haematologist who specialises in bleeding disorders. In Australia, these haematologists can be found at Haemophilia Centres or Services which are at some major hospitals. Talk to your general practitioner or your gynaecologist about a referral.
There are a variety of issues related to diagnosing VWD, including:
- Other family members may need to be tested for VWD
- Possible implications for employment, health insurance cover and carrying the VWD gene
- Decisions will need to be made, in consultation with your Haemophilia Centre or Service, about which treatment options will be the most suitable.
Haemophilia Centre social workers, counsellors and nurses are available to help people deal with these issues.