A 40-year-old man with deep vein thrombosis is found to have an abnormal platelet aggregation test: normal aggregation with ADP, collagen, epinephrine, and ristocetin, but ABSENT aggregation with ristocetin corrected by adding normal plasma. He has a mild bleeding history. Which condition is diagnosed?

• A von Willebrand disease type 1 — reduced vWF; ristocetin aggregation reduced/absent, corrected by adding normal plasma (containing vWF) ✓
• B Bernard-Soulier syndrome — absent GP Ib-IX-V; ristocetin aggregation absent, NOT corrected by normal plasma
• C Glanzmann thrombasthenia — absent GP IIb/IIIa; absent aggregation with all agonists EXCEPT ristocetin
• D Platelet factor 3 deficiency — selective defect in phosphatidylserine exposure on activated platelets

Explanation

The RISTOCETIN CORRECTION TEST is key: absent ristocetin-induced platelet aggregation (RIPA) that is CORRECTED by adding normal plasma (containing vWF) points to von Willebrand disease — the patient's platelets are normal but lack adequate vWF to agglutinate. In Bernard-Soulier syndrome, ristocetin RIPA is absent and NOT corrected by normal plasma because the platelet receptor (GP Ib-IX-V) is absent/abnormal. In Glanzmann thrombasthenia, all agonist aggregation is absent except ristocetin (which works through GP Ib, not GP IIb/IIIa). Normal aggregation with ADP/collagen rules out Glanzmann.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.