title: Influence of apixaban on commonly used coagulation assays: results from the Belgian national External Quality Assessment Scheme.
abstract: BACKGROUND
  The Belgian national External Quality Assessment Scheme performed a survey to assess the effect of the direct oral anticoagulant apixaban on the coagulation assays prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and antithrombin as performed with a large number of reagent/instrument combinations.
  
  
  METHODS
  Four lyophilized plasma samples spiked with apixaban (0, 41, 94 and 225 ng/mL) were sent to the 195 Belgian and Luxembourg clinical laboratories performing coagulation testing.
  
  
  RESULTS
  PT and aPTT were barely influenced at the concentrations tested. At 225 ng/mL apixaban, PT and aPTT clotting times were only 1.15 times longer than at 0 ng/mL. Among PT reagents, RecombiPlasTin 2G®showed a slightly higher sensitivity with 225 ng/mL apixaban prolonging the PT clotting time 1.3-fold. Among aPTT reagents, there was no appreciable difference in sensitivity. Fibrinogen results were unaffected by the presence of apixaban, but antithrombin activity was considerably overestimated when measured with a FXa-based assay. At 225 ng/mL apixaban, the median percentage increase in antithrombin level was 31% when measured with the Liquid Antithrombin®reagent and 44% with the Innovance Antithrombin®reagent.
  
  
  CONCLUSIONS
  Our data provide clinical laboratories with useful information on the impact of apixaban on their routine coagulation assays.
authors.affiliation: Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-2238-3773
authors.initials: M
authors.lastname: Van Blerk
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Bailleul
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Chatelain
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Demulder
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Devreese
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Douxfils
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Jacquemin
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Jochmans
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Mullier
authors.affiliation: EQA Advisory Board, Brussels, Belgium.
authors.forename: W
authors.initials: W
authors.lastname: Wijns
authors.affiliation: Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: China
authors.affiliation: Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Vernelen
authors.affiliation: Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: M R
authors.initials: MR
authors.lastname: Soumali
mesh_terms: D000991:Antithrombins / Q000097:blood; D001530:Belgium; D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests / Q000379:methods / Q000592:standards*; D016903:Drug Monitoring; D065427:Factor Xa Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D005340:Fibrinogen / Q000096:biosynthesis; D006801:Humans; D010314:Partial Thromboplastin Time; D011517:Prothrombin Time; D011720:Pyrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D011728:Pyridones / Q000494:pharmacology* / Q000627:therapeutic use; D011785:Quality Assurance, Health Care
chemical_list: D000991:Antithrombins; D065427:Factor Xa Inhibitors; D011720:Pyrazoles; D011728:Pyridones; C522181:apixaban; D005340:Fibrinogen
keywords: antithrombin; apixaban; direct oral anticoagulants; external quality assessment; routine coagulation assays