Point of care testing to monitor INR control in patients with antiphospholipid syndrome

Patients with antiphospholipid syndrome (APS) typically require lifelong warfarin anticoagulation following a thrombotic event due to a significant risk of recurrent thrombosis. Point of care testing (POCT) to monitor INR is discouraged in patients with APS as interactions between antiphospholipid antibodies and thromboplastin used for INR testing may influence results. Review of INR testing in 36 APS patients showed 87.2% of paired POCT and venous INRs (n = 94) having acceptable variation (≤0.5 difference), and high correlation (r = 0.9) excluding INRs ≥4.8. Six‐month TTR was comparable for APS patients using POCT (57.1% ± 24.8%) to those using venous INR monitoring (59.2% ± 23.2%) (p = 0.66). These results support POCT management of APS but requires further study.