Brief observationInterpretation of Point-of-care INR Results in Patients Treated with Dabigatran
Section snippets
Methods
The study was approved by a Local Research Ethics Committee, and all 4 subjects (2 male and 2 female) gave written informed consent. Venous blood samples (20 mL in total) were collected from each volunteer into 3.2% sodium citrate tubes, separated into aliquots, spiked with increasing concentrations (50-1400 ng/mL) of dabigatran (Boehringer Ingelheim, Ingelheim, Germany), and incubated at 37°C for at least 5 minutes. Whole blood samples (100 μL) were applied to individual disposable prothrombin
Results
Across the dabigatran concentration range tested, INR levels were consistently higher (by 2- to 4-fold) when measured using the Hemochron Jr. point-of-care device compared with the laboratory-based coagulometer (Figure 1). At representative plasma concentrations of dabigatran, likely to be observed in patients, at a dose of 150 mg twice daily (60-275 ng/mL),3 whole blood point-of-care INR values increased from 1.7 to 4.0, compared with 1.1 to 1.5 when measured with the laboratory coagulometer (
Discussion
The results of this study confirm the previous case reports5, 6 and highlight the risks associated with using INR measurements obtained from point-of-care devices as a basis for clinical decision-making in patients receiving dabigatran. In general, INR levels using the point-of-care device were 2- to 4-fold higher than those measured using routine laboratory monitoring. The cause of elevated measurements with this point-of-care device remains unclear but may be due to lack of calibration of the
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Funding: Boehringer Ingelheim.
Conflict of Interest: JvR and AC are employees of Boehringer Ingelheim.
Authorship: All authors had access to the data and played a role in writing this manuscript.