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.
-
Oct 30, 2026, 16:44Shehab Mohamed: Recognizing Isolated Thrombocytopenia as a Presentation of MDS
-
Oct 30, 2026, 16:40Amrita Sarkar: Advancing the Diagnosis of Anti-PF4 Syndromes
-
Oct 30, 2026, 16:35James Garrard: Driving Innovation in Stroke Care Through Global Collaboration
-
Oct 30, 2026, 16:19Cesar de Almeida Neto: Hemo 2026 Roundtable Focuses on the Challenges of Patient Blood Management
-
Oct 30, 2026, 16:01Marilena Vrana: The Case for Retaining Immunoglobulins on the EU Critical Medicines List
-
Oct 30, 2026, 15:53Ilenia Calcaterra: Patient Blood Management Across Complex Hematological Conditions
-
Oct 30, 2026, 15:40Isabella Presch: The Practicalities of Gene Therapy Adoption in Hemophilia
-
Oct 30, 2026, 15:12Edward C.C. Wong: Navigating the Implications of the 2026 ASH Guidelines for Blood Donation
-
Oct 30, 2026, 14:53Pall T. Onundarson: Anticoagulation Guidelines Under the Influence of Pharmaceuticalisation