title: Measurement of dabigatran plasma concentrations by calibrated thrombin clotting time in comparison to LC-MS/MS in human volunteers on dialysis.
abstract: BACKGROUND
  Dabigatran etexilate is an oral direct thrombin inhibitor. Although routine anticoagulation monitoring with dabigatran is not usually required, a simple and precise laboratory test to measure dabigatran concentrations in patient plasma may be useful in certain clinical circumstances, such as emergency situations. The HEMOCLOT(®) Thrombin Inhibitors assay has demonstrated accurate and precise determination of dabigatran concentrations within a range of 50-500 ng/ml. The objective of this study was to assess comparability of dabigatran concentrations determined by HEMOCLOT(®) and by liquid chromatography/tandem mass spectrometry (LC-MS/MS) in plasma samples from human volunteers with end-stage renal disease (ESRD) undergoing regular haemodialysis (HD) during a Phase I study.
  
  
  METHODS
  Overall, 304 plasma samples were obtained from seven ESRD patients in dabigatran steady-state for measurement by HEMOCLOT(®) (calibrated diluted thrombin time [dTT]) and by LC-MS/MS. Agreement of dabigatran concentrations was assessed by regression analysis and difference plots.
  
  
  RESULTS
  The measurements of calibration standards of the HEMOCLOT(®) assay showed excellent precision with coefficients of variation <5%. Accuracy determined by analysis of two quality control samples was 90% and 111%. HEMOCLOT(®)-derived dabigatran plasma concentrations paralleled those obtained by LC-MS/MS. The mean ratio of the LC-MS/MS and dTT-derived concentrations was 0.955 (67% limits of agreement: 0.771-1.18).
  
  
  CONCLUSIONS
  The HEMOCLOT(®) Thrombin Inhibitors assay is suitable for measuring dabigatran plasma concentrations in volunteers with ESRD undergoing haemodialysis. The agreement between dabigatran concentrations determined by the HEMOCLOT(®) assay and the LC-MS/MS reference method met bioanalytical acceptance criteria.
authors.affiliation: Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schmohl
authors.affiliation: Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Gansser
authors.affiliation: Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany.
authors.forename: Viktoria
authors.initials: V
authors.lastname: Moschetti
authors.affiliation: Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany. Electronic address: joachim.stangier@boehringer-ingelheim.com.
authors.forename: Joachim
authors.initials: J
authors.lastname: Stangier
mesh_terms: D000328:Adult; D000991:Antithrombins / Q000097:blood*; D001777:Blood Coagulation; D001780:Blood Coagulation Tests; D002853:Chromatography, Liquid / Q000379:methods; D000069604:Dabigatran / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008875:Middle Aged; D006435:Renal Dialysis; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013917:Thrombin / Q000378:metabolism; D055815:Young Adult
chemical_list: D000991:Antithrombins; D013917:Thrombin; D000069604:Dabigatran
keywords: Dabigatran etexilate; Diluted thrombin time; HEMOCLOT(®) Thrombin Inhibitors assay; LC-MS/MS; Method comparison; end-stage renal disease