Discordance between aPTT and anti-factor Xa levels and implications in patients receiving intravenous unfractionated heparin therapy

Abstract

Heparin, one of the world’s oldest anticoagulation medications, accelerates the rate ofinhibition of previously activated clotting factors. It is most often used in the prophylaxis andtreatment of thromboembolic disorders and complications associated with atrial fibrillation.The two most common ways to monitor plasma heparin levels and anticoagulation therapyare the activated partial thromboplastin time (aPTT) and anti-factor Xa assay (anti-Xa). Thisarticle assesses the performance of aPTT and anti-Xa monitoring protocols and analyzes thediscordance between aPTT and anti-Xa levels and its clinical implications in patients receivingintravenous heparin therapy.