title: Laboratory monitoring of rivaroxaban and assessment of its bleeding risk.
abstract: BACKGROUND
  The aims of this study were to investigate the effects of rivaroxaban on routine coagulation assays using our local, widely available, reagents and to study the relationship between sensitive coagulation assays and bleeding risk caused by rivaroxaban.
  
  
  METHODS
  Prothrombin time (PT), activated partial thromboplastin time (APTT) and anti-factor Xa (FXa) chromogenic assays (Biophen DiXaI) and inhibition of FXa activity were performed in normal pooled plasma (NPP) spiked with rivaroxaban and plasma samples from patients treated with rivaroxaban.
  
  
  RESULTS
  In vitro, the linear correlation coefficient of measured concentrations of rivaroxaban, by Biophen DiXaI, and spiked concentrations of rivaroxaban was 0.99. PT and APTT showed good linear correlation with rivaroxaban concentrations, while other assays showed poor correlation. In vivo, PT showed a moderate linear correlation with rivaroxaban concentrations while APTT had a weak correlation with rivaroxaban concentrations. In vitro and in vivo, the rivaroxaban concentrations, measured by Biophen DiXaI, always showed good correlation with the inhibition of FXa activity, and PT values showed moderate correlation with the inhibition of FXa activity.
  
  
  CONCLUSIONS
  Biophen DiXaI can be considered as a quantitative method to monitor the anticoagulation activity of rivaroxaban, and could be used to evaluate bleeding risk caused by rivaroxaban. The PT reagent (Thrombosis S) could be considered as a rough method to monitor the anticoagulation activity of rivaroxaban and evaluate bleeding risk caused by rivaroxaban.
authors.affiliation: a Department of Pharmacy, The Fifth People's Hospital of Shanghai , Fudan University , Shanghai , China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: a Department of Pharmacy, The Fifth People's Hospital of Shanghai , Fudan University , Shanghai , China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Qian
authors.affiliation: a Department of Pharmacy, The Fifth People's Hospital of Shanghai , Fudan University , Shanghai , China.
authors.forename: Guang
authors.initials: G
authors.lastname: Qian
authors.affiliation: a Department of Pharmacy, The Fifth People's Hospital of Shanghai , Fudan University , Shanghai , China.
authors.forename: Guangchun
authors.initials: G
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D001777:Blood Coagulation / Q000187:drug effects*; D065427:Factor Xa Inhibitors / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time; D000069552:Rivaroxaban / Q000627:therapeutic use*; D020246:Venous Thrombosis / Q000517:prevention & control; D055815:Young Adult
chemical_list: D065427:Factor Xa Inhibitors; D000069552:Rivaroxaban
keywords: Rivaroxaban; anti-factor Xa chromogenic assay; bleeding risk; inhibition of factor Xa activity; monitoring; prothrombin time