title: Laboratory measurements of the oral direct factor Xa inhibitor edoxaban: comparison of prothrombin time, activated partial thromboplastin time, and thrombin generation assay.
abstract: OBJECTIVE
  Edoxaban, an oral direct factor Xa inhibitor, does not require routine monitoring. However, assessment of the anticoagulant effects may be required in certain situations.
  
  
  METHODS
  We investigated the effects of edoxaban on prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin generation using human platelet-poor plasma (PPP) or platelet-rich plasma (PRP).
  
  
  RESULTS
  Edoxaban concentration-dependently prolonged PT and aPTT. There was a considerable variation in the magnitude of PT prolongation among the reagents used. The variability in aPTT prolongation among the reagents was smaller than that of PT. Edoxaban concentration-dependently inhibited thrombin generation, with a more potent effect seen in PPP than in PRP. Thrombin generation assay was three times more sensitive to edoxaban than PT and aPTT.
  
  
  CONCLUSIONS
  PT had disadvantages of a large variability among different PT reagents. aPTT could be used as a conventional and convenient test with a smaller variation among reagents. Thrombin generation was the most sensitive assay.
authors.affiliation: From Biological Research Laboratories, R &D Division, Daiichi Sankyo, Tokyo, Japan. morishima.yoshiyuki.t4@daiichisankyo.co.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Morishima
authors.affiliation: From Biological Research Laboratories, R &D Division, Daiichi Sankyo, Tokyo, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Kamisato
mesh_terms: D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests / Q000379:methods*; D065427:Factor Xa Inhibitors / Q000494:pharmacology*; D006801:Humans; D010314:Partial Thromboplastin Time; D053657:Platelet-Rich Plasma / Q000187:drug effects; D011517:Prothrombin Time; D011725:Pyridines / Q000494:pharmacology*; D013844:Thiazoles / Q000494:pharmacology*; D013917:Thrombin / Q000187:drug effects*
chemical_list: D065427:Factor Xa Inhibitors; D011725:Pyridines; D013844:Thiazoles; D013917:Thrombin; C552171:edoxaban
keywords: Activated partial thromboplastin time; Coagulation assay; Direct factor Xa inhibitor; Monitoring; Prothrombin time; Thrombin generation assay