title: Testing for dabigatran and rivaroxaban by clinical laboratories.
abstract: Rivaroxaban and dabigatran are among the newest anticoagulants, and measuring their concentration in patients is a new challenge for clinical laboratories. We analyzed data from the ECAT proficiency program to determine how well the assays are performing in clinical laboratories internationally. Most laboratories received a passing grade (Z score <3) for the results of their dabigatran and rivaroxaban testing. Failing Z scores were not associated with any particular method. With dabigatran, some homemade calibrators gave higher results than the commercially available calibrators. There were no significant differences among the instruments or the 5 reagents in use, but results showed inter-laboratory variability that could have clinical significance. The 3 reagents with the lowest number of users had poor inter-laboratory precision. Ten different anti-Xa reagents were in use for rivaroxaban testing. One reagent gave lower results than other reagents at 100 ng/mL but not at 300 ng/mL. There were no significant differences among the different rivaroxaban calibrators or instruments. In conclusion, inter-laboratory precision could be improved for both dabigatran and rivaroxaban assays. Homemade dabigatran calibrators differed from commercially available calibrators, and there was a statistically significant difference between some of the rivaroxaban reagents. About 10% of results received failing Z scores or passed but fell in a range that require the laboratory to investigate for bias or other inaccuracy in their method. Am. J. Hematol. 91:E464-E467, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts. evancott@mgh.harvard.edu.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Van Cott
authors.affiliation: Department of Pathology, University of Utah, ARUP Laboratories, Salt Lake City, Utah.
authors.forename: Kristi J
authors.initials: KJ
authors.lastname: Smock
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Pathology/Laboratory Medicine Hofstra Northwell School of Medicine, Lake Success, New York.
authors.forename: Peihong
authors.initials: P
authors.lastname: Hsu
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Zantek
authors.affiliation: ECAT Foundation, Voorschoten, Netherlands.
authors.forename: Piet
authors.initials: P
authors.lastname: Meijer
mesh_terms: D000925:Anticoagulants / Q000494:pharmacology; D000991:Antithrombins; D001780:Blood Coagulation Tests / Q000592:standards*; D002138:Calibration; D064790:Clinical Laboratory Services / Q000592:standards*; D000069604:Dabigatran / Q000494:pharmacology*; D065427:Factor Xa Inhibitors; D006801:Humans; D007202:Indicators and Reagents; D015588:Observer Variation; D000069552:Rivaroxaban / Q000494:pharmacology*
chemical_list: D000925:Anticoagulants; D000991:Antithrombins; D065427:Factor Xa Inhibitors; D007202:Indicators and Reagents; D000069552:Rivaroxaban; D000069604:Dabigatran