title: Determination of dabigatran in plasma, serum, and urine samples: comparison of six methods.
abstract: BACKGROUND
  Assessing the anticoagulant effect of dabigatran may be useful in certain clinical settings. When plasma sampling is not available, serum or urine samples may provide another option for dabigatran determinations.
  
  
  METHODS
  Dabigatran was assessed in patients on treatment under real-life conditions in plasma samples by four clotting time-based assays and in plasma, serum, and urine samples by two chromogenic substrate methods.
  
  
  RESULTS
  The concentrations of dabigatran in patients' plasma samples were not different for the Hemoclot test (106.8±89.4 ng/mL) and the ecarin clotting time (ECT, 109.5±74.5 ng/mL, p=0.58). Activated partial thromboplastin time and prothrombinase-induced clotting time showed low correlations with the other assays. Chromogenic assays measured similar concentrations as Hemoclot and ECT. For both chromogenic assays, the concentrations of dabigatran were about 70% lower in serum than in plasma samples (p<0.0001). The intra-class coefficient (ICC, Bland-Altman analysis) was strong comparing ECT, Hemoclot thrombin inhibitor (HTI) assay, and the two chromogenic assays (r=0.889-0.737). The ICC was low for comparisons of the chromogenic assays of serum vs. plasma values (ICC, 0.15 and 0.66). The ICC for the determination of dabigatran in urine samples by the two chromogenic assays (5641.6±4319.7 and 4730.0±3770.2 ng/mL) was 0.737.
  
  
  CONCLUSIONS
  ECT, HTI, and chromogenic assays can be used to determine dabigatran in plasma samples from patients under real-life conditions. Chromogenic assays require further improvement to reliably measure dabigatran in serum samples. Dabigatran concentrations in urine samples can also be determined quantitatively.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Du
authors.forename: Christel
authors.initials: C
authors.lastname: Weiss
authors.forename: Giese
authors.initials: G
authors.lastname: Christina
authors.forename: Sandra
authors.initials: S
authors.lastname: Krämer
authors.forename: Martin
authors.initials: M
authors.lastname: Wehling
authors.forename: Roland
authors.initials: R
authors.lastname: Krämer
authors.forename: Job
authors.initials: J
authors.lastname: Harenberg
mesh_terms: D000991:Antithrombins / Q000097:blood* / Q000494:pharmacology / Q000652:urine*; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests; D002863:Chromogenic Compounds / Q000737:chemistry*; D000069604:Dabigatran / Q000097:blood* / Q000494:pharmacology / Q000652:urine*; D010450:Endopeptidases / Q000737:chemistry / Q000378:metabolism; D006801:Humans
chemical_list: D000991:Antithrombins; D002863:Chromogenic Compounds; D010450:Endopeptidases; C020097:ecarin; D000069604:Dabigatran