Von Willebrand's disease can be hard to diagnose. If you have symptoms that suggest a blood clotting disorder, such as frequent nosebleeds or heavy menstrual periods, a health professional will take a blood sample and have it tested in a lab.

Tests for von Willebrand's disease may measure:

• Von Willebrand factor antigen.
• Bleeding time.
• Von Willebrand factor activity levels, using a test such as PTT (partial thromboplastin time).

Early diagnosis of mild von Willebrand's disease allows health professionals to identify when you may need special treatment in order to help prevent severe bleeding problems. A definite diagnosis of von Willebrand's disease depends on:⁴

• A finding of low levels of von Willebrand factor in your blood on more than one occasion.
• A history of excessive bleeding.
• Genetic testing. It can show a defect in your von Willebrand factor and what type or subtype of von Willebrand's disease you have.