From Activated Partial Thromboplastin Time to Antifactor Xa and Back Again

Academic Article


  • Objectives: Monitoring is essential to safe anticoagulation prescribing and requires close collaboration among pathologists, clinicians, and pharmacists. Methods: We describe our experience in the evolving strategy for laboratory testing of unfractionated heparin (UFH). Results: An intrainstitutional investigation revealed significant discordance between activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) assays, prompting a transition from the former to the latter in 2013. With the increasing use of oral factor Xa inhibitors (eg, apixaban, rivaroxaban, edoxaban, betrixaban), which interfere with the anti-Xa assay, we adapted our protocol again to incorporate aPTT in patients admitted on oral Xa inhibitors who require transition to UFH. Conclusions: Our experience demonstrates key challenges in anticoagulation and highlights the importance of clinical pathologists in helping health systems adapt to the changing anticoagulation landscape.
  • Digital Object Identifier (doi)

    Author List

  • May JE; Siniard RC; Taylor LJ; Marques MB; Gangaraju R
  • Start Page

  • 321
  • End Page

  • 327
  • Volume

  • 157
  • Issue

  • 3