Understanding Lab Tests for Von Willebrand Disease
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Von Willebrand Disease (VWD) is the most common inherited bleeding disorder, affecting how blood clots. It occurs when the body either doesn't make enough of a protein called von Willebrand factor or the protein doesn't work properly. This genetic condition can cause prolonged bleeding after injuries, surgeries, or dental work.
Recommended Test
Prothrombin Time (PT) (INR) and Partial Thromboplastin Time (PTT)
This coagulation test is crucial for diagnosing Von Willebrand Disease. The PTT portion of this test is typically prolonged in people with VWD because they have either low levels of von Willebrand factor or the factor doesn't function properly. Von Willebrand factor is essential for helping platelets stick together and form clots, so when it's deficient or dysfunctional, the blood takes longer to clot, resulting in an extended PTT.
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Diagnosing Von Willebrand Disease with Blood Tests
Blood tests are essential for diagnosing Von Willebrand Disease. Since the condition affects blood clotting mechanisms, specialized coagulation tests can reveal abnormal bleeding patterns and help confirm the presence of this genetic disorder.
Understanding the Results
A prolonged PTT result may indicate Von Willebrand Disease, but additional specialized tests are often needed to confirm the diagnosis and determine the specific type and severity of the condition. Your healthcare provider will interpret these results in the context of your symptoms and medical history.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.
