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Antiphospholipid Syndrome — RACP Adult Medicine MCQ

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ModerateHaematologyAntiphospholipid SyndromeRACP Adult Medicine

A 28-year-old woman presents with recurrent unprovoked DVTs. She is found to have persistently positive lupus anticoagulant and anti-cardiolipin IgG antibodies on two occasions 14 weeks apart. She has no history of pregnancy loss. She is currently on warfarin with an INR target of 2.5. What is the appropriate INR target?

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Correct answer: D — 2.0–3.0

For APS with VTE, the recommended INR target on warfarin is 2.0–3.0. Higher-intensity anticoagulation (INR 3.0–4.0) was not shown to be superior to standard intensity in the WAPS trial and carries increased bleeding risk. DOACs should NOT be used in APS (especially triple-positive) due to inferior outcomes demonstrated in the TRAPS trial. Lifelong anticoagulation is recommended.

Reference: eTG – 2025 – Haematology; ISTH – 2020 – APS Anticoagulation Guidance