Sékouba Sidimé/LinkedIn
Jun 2, 2026, 19:42
Sékouba Sidimé: vWD vs Hemophilia A – The Classic USMLE Step 1 trap in Hematology
Sékouba Sidimé, Internal Medicine Physician, shared a post on LinkedIn:
“vWD vs Hemophilia A – The No. 1 USMLE Step 1 trap in Hematology
One lab result tells them apart.Here’s what you need to know:
von Willebrand Disease
- Prolonged aPTT, prolonged Bleeding time, decreased Ristocetin
- Female with a family history and mucocutaneous bleeding
- Treatment: Desmopressin (DDAVP)
Hemophilia A
- Prolonged aPTT , Bleeding time normal, Ristocetin normal
- Male with hemarthroses
- Treatment: Factor VIII replacement
The key:
vWF carries Factor VIII — decreased vWF results in secondary reduction of Factor VIII.
That’s why vWD affects both aPTT AND bleeding time.
Hemophilia A affects aPTT only.
If the examiner mentions Ristocetin then think vWD. Every time.”

Stay updated with Hemostasis Today.
-
Jul 26, 2026, 01:48Rob Maloney: Why Global Diagnosis is the Missing Piece in Bleeding Disorder Care
-
Jul 26, 2026, 01:35Moustafa Abdou: Ehlers-Danlos Syndrome – Why Collagen Matters for Hemostasis
-
Jul 26, 2026, 01:25Vrisha Shah: Exploring Transgenic Mouse Models for Pregnancy Outcomes at ISTH 2026
-
Jul 26, 2026, 01:06Christine Bork: Why Misinformation Around a Single Vitamin Postpartum is Putting Babies at Risk
-
Jul 26, 2026, 00:44A Significant Step Forward For People With Bleeding Disorders In The Dominican Republic – WFH
-
Jul 25, 2026, 18:00The Evolving Landscape of Factor Replacement Therapy – EAHAD
-
Jul 25, 2026, 17:43Heghine Khachatryan: Advancing Care for Women and Girls With Hemophilia
-
Jul 25, 2026, 17:00Revathy R Menon: A Memorable Milestone at the 39th ISBT Congress
-
Jul 25, 2026, 16:19Nicola Potere: From Scientific Exchange to Global Collaboration at ISTH 2026