title: Multi-analyte analysis of non-vitamin K antagonist oral anticoagulants in human plasma using tandem mass spectrometry.
abstract: BACKGROUND
  The non-vitamin K antagonist oral anticoagulants (NOACs) apixaban, dabigatran, and rivaroxaban are being administered in fixed doses without routine monitoring of anticoagulant activities. Despite this key advantage over vitamin K antagonists (VKAs), assessment of anticoagulant intensities is required in various clinical circumstances. We developed a multi-analyte approach for mass spectrometric analysis of NOACs in human plasma.
  
  
  METHODS
  Plasma samples were precipitated with acetonitrile. Separation was achieved by liquid chromatography using a C18 column and a gradient elution within a run time of 2.5 min. Positive electrospray ionization was used and ion transitions monitored by a triple quadrupole mass spectrometer. Stable-isotope-labeled analogues of analytes were employed as internal standards for quantitative analysis. Certified external quality control samples were obtained for external validation.
  
  
  RESULTS
  For all analytes, linearity could be demonstrated over the concentration range of 1-500 μg/L (R2>0.999), and the calculated limits of quantification were <1 μg/L. Results for inter- and intra-day assay precision and trueness were obtained using internal quality control samples and remained within the acceptance criterion of ±15%. External quality control samples were measured at the specified nominal values with inter- and intra-day precisions <14%. Matrix effects were fully compensated by co-eluting internal standards, which in turn did not relevantly influence ionization efficiency.
  
  
  CONCLUSIONS
  The method enables rapid and reliable simultaneous determination of NOAC concentrations in human plasma. It was successfully introduced into clinical practice; a case with rivaroxaban overdose is presented to exemplify the method's applicability.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Blaich
authors.forename: Carsten
authors.initials: C
authors.lastname: Müller
authors.forename: Guido
authors.initials: G
authors.lastname: Michels
authors.forename: Martin H J
authors.initials: MH
authors.lastname: Wiesen
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D002853:Chromatography, Liquid; D000069604:Dabigatran / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D006801:Humans; D011720:Pyrazoles / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D011728:Pyridones / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D011786:Quality Control; D000069552:Rivaroxaban / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D053719:Tandem Mass Spectrometry; D014812:Vitamin K / Q000037:antagonists & inhibitors
chemical_list: D000925:Anticoagulants; D011720:Pyrazoles; D011728:Pyridones; D014812:Vitamin K; C522181:apixaban; D000069552:Rivaroxaban; D000069604:Dabigatran