The addition of idarucizumab to plasma samples containing dabigatran allows the use of routine coagulation assays for the diagnosis of hemostasis disorders

Abstract

To cite this article: Jacquemin M, Toelen J, Schoeters J, van Horenbeeck I, Vanlinthout I, Debasse M, Peetermans M, Vanassche T, Peerlinck K, van Ryn J, Verhamme P. The addition of idarucizumab to plasma samples containing dabigatran allows the use of routine coagulation assays for the diagnosis of hemostasis disorders. J Thromb Haemost 2015; 13: 2087-92.Summary. Background: The anticoagulant effect of dabigatran can be approximated by its prolongation of routine coagulation assays. Consequently, dabigatran also interferes with thrombophilia screening or with diagnosing hemostasis disorders that have developed after the initiation of anticoagulant treatment, such as vitamin K deficiency or acquired hemophilia A. Objectives: This study was carried out to determine whether idarucizumab, a humanized antibody fragment that binds dabigatran, could fully neutralize dabigatran in routine diagnostic coagulation assays conducted in vitro, thereby preventing false-positive or false-negative diagnostic readouts. Methods: Preliminary experiments identified coagulation assays that were sensitive to dabigatran, and identified a concentration of idarucizumab that neutralized the effects of dabigatran. These assays were then carried out with patient and control plasma samples spiked with dabigatran, with or without a molar excess of idarucizumab. Results: Dabigatran altered the prothrombin time, activated partial thromboplastin time and thrombin time, and the measurement of intrinsic and extrinsic factor levels. Screening and confirmation tests used for lupus anticoagulant detection were prolonged by dabigatran, falsely suggesting the presence of lupus anticoagulant. Conversely, the addition of dabigatran falsely corrected an abnormal activated protein C resistance ratio. Addition of idarucizumab completely normalized these measurements, and allowed the correct identification of normal and abnormal samples with these assays. Conclusions: In vitro addition of idarucizumab to plasma samples containing dabigatran fully neutralizes the drug, and facilitates the use of routine coagulation assays to allow the diagnosis of hemostasis disorders that may be concurrently present in patients taking dabigatran.

The adsorption of dabigatran is as efficient as addition of idarucizumab to neutralize the drug in routine coagulation assays

“…In agreement with our previous experiments, dabigran levels remained below the detection limit of our assay (3.4 ng/mL) when up to 5000 ng/mL dabigatran was mixed with 625 μg/mL idarucizumab . With higher concentration of dabigatran, the residual concentration of the drug raised above 350 μg/mL, the upper limit of the assay, despite the addition of idarucizumab (Figure A).…”

“…In a first series of experiments, we compared the amounts of dabigatran spiked into 1 mL of normal plasma that could be neutralized either by one tablet of adsorbent or by a given concentration of idarucizumab. A single final concentration of 625 μg/mL of idarucizumab was selected for these experiments as we had previously shown that in the absence of dabigatran such a concentration of idarucizumab did not interfere with any of the routine coagulation tests …”

“…All assays were performed on an ACL‐TOP 500 (Werfen, Brussels, Belgium), with the manufacturer's standard protocol as previously described . The following reagents were used HemosIL SynthASil, HemosIL Thrombin Time, HemosIL Recombiplastin, COATEST APC Resistance V (Werfen).…”

“…The following reagents were used HemosIL SynthASil, HemosIL Thrombin Time, HemosIL Recombiplastin, COATEST APC Resistance V (Werfen). PT‐, APTT‐ and Russel viper venom time (RVVT) ‐based lupus anticoagulant screening and confirmation tests were carried out with 50‐fold diluted Dade Innovin (Dade Behring, Brussels, Belgium), HemosIL Recombiplastin, PTT‐LA (Diagnostica Stago, Asnieres sur Seine, France), Actin FS (Siemens, Beersel, Belgium), HemosIL DRVVT Screen (Werfen), and HemosIL DRVVT Confirm (Werfen) respectively . Dabigatran levels were measured with a diluted thrombin time test, Hemoclot Thrombin Inhibitors (Hyphen BioMed; Nodia).…”

“…Idarucizumab has been successfully used in patients treated with dabigatran who developed live‐threatening bleedings or who needed an urgent surgical intervention . We have recently demonstrated that the addition of idarucizumab to plasma samples prevented any interference of dabigatran in coagulations assays, thereby allowing to carry out detailed hemostasis and thrombophilia screenings for patients taking the drug …”