Assessment of direct oral anticoagulant assay use in clinical practice

  • Tina M. GuEmail author
  • David A. Garcia
  • Daniel E. Sabath


There are no clear and consistent guidelines on how to utilize DOAC assays, and reports on the use of DOAC levels in clinical practice is limited. The objective of this study was to analyze why DOAC levels are ordered, how the results affect clinical decision-making, and to determine if DOAC assays are utilized appropriately. This was a retrospective chart review study analyzing 150 dabigatran, rivaroxaban, and apixaban levels performed at a single institution. The majority of DOAC assays were ordered in situations or special patient populations where confirming absence or detecting presence of drug may be useful. The most common indication for ordering assays was prior to an invasive procedure. Most DOAC levels were timed appropriately but peak levels were most likely to be incorrectly ordered. Clinical decisions following level results depended on indication for ordering and were most commonly used to determine whether or not to proceed with an invasive procedure. The results of our study suggest while DOAC assays are generally ordered for useful indications, there is still a lack of understanding of when levels should be drawn and how to interpret DOAC assay results.


Anticoagulant agents Dabigatran Rivaroxaban Apixaban Drug monitoring 



We would like to acknowledge Ann K. Wittkowsky, PharmD, CACP, FASHP, FCCP, retired Director of Anticoagulation Services at University of Washington Medical Center for her thoughtful comments and help with earlier versions of this manuscript.

Author contributions

TMG, DAG, and DES designed the study. TMG generated the data. TMG, DAG, and DES interpreted the results. TMG drafted the manuscript. DAG and DES critically revised the manuscript.

Compliance with ethical standards

Conflict of interest

T. M. Gu and D. E. Sabath declare they have no conflict of interests. D. A. Garcia has received research support from Daiichi Sankyo and consulting fees from Janssen.

Ethical approval

This was a retrospective study approved by the institutional review board at University of Washington Medicine. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

For this type of study formal consent is not required.

Supplementary material

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Supplementary Fig. 1 Clinical decisions following assay results in the setting of acute hemorrhage. The following decisions refer to changes made at discharge: restarted DOAC, discontinued DOAC, and switched anticoagulant. (TIFF 1142 KB)
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Supplementary Fig. 2 Clinical decisions following assay results in the setting of acute thrombosis. (TIFF 1142 KB)
11239_2018_1793_MOESM3_ESM.tiff (1.1 mb)
Supplementary Fig. 3 Clinical decisions following assay results for drug interaction or renal impairment. (TIFF 1142 KB)
11239_2018_1793_MOESM4_ESM.docx (17 kb)
Supplementary material 4 (DOCX 16 KB)
11239_2018_1793_MOESM5_ESM.docx (16 kb)
Supplementary material 5 (DOCX 16 KB)


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of PharmacyUniversity of WashingtonSeattleUSA
  2. 2.Division of HematologyUniversity of WashingtonSeattleUSA
  3. 3.Department of Laboratory MedicineUniversity of WashingtonSeattleUSA

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