INR Management of an Antiphospholipid Syndrome Patient With Point-of-Care INR Testing

Abstract

Management of patients with antiphospholipid syndrome on warfarin therapy can be challenging. The international normalized ratio (INR) of patients with antiphospholipid syndrome can be falsely elevated. This elevation is thought to be reflective of the reaction of the antiphospholipid antibody with the thromboplastin used to measure the protime. This false elevation can be seen in both venipuncture and point-of-care results. This discrepancy is usually more apparent in patients with whose INR is tested using point of care. As a result, there is a preference for venipuncture INR testing in most patients with antiphospholipid syndrome requiring warfarin therapy. In our case, we highlight one patient who we correlated her venipuncture INR with point-of-care INR as well as a chromogenic factor X level in order to manage her INR by point-of-care INR testing.