Because vWD is usually mild, many people do not experience any problems, and the condition may be undiagnosed for a long time. Often, the first indication that there may be a problem with blood clotting comes after a minor operation, such as a tooth extraction. Once the problem is suspected, doctors can run tests to diagnose the disease.
The tests consist of taking a personal and family history of diseases from the patient, which may give clues to clotting problems in the past, or in relatives, and some blood tests. These tests measure the time that blood takes to clot and the levels of clotting factors present, and compares them with those in people known not to have vWD.
The diagnosis may be complicated and take some time because many people with vWD have levels of clotting factors in their blood that are nearly as high as normal. Worrying about going to hospital and having a blood test can also make these levels increase. Therefore, the tests may need to be carried out on more than one occasion. Diagnosis in one family member can often lead to the identification of the disease in other family members.