A New Test for the Detection of Direct Oral Anticoagulants (Rivaroxaban and Apixaban) in the Emergency Room Setting

Galit H Frydman; Felix Ellett; Elizabeth M Van Cott; Douglas Hayden; Maulik Majmudar; Charles R Vanderburg; Haley Dalzell; Divya L Padmanabhan; Nick Davis; Julianne Jorgensen; Mehmet Toner; James G Fox; Ronald G Tompkins

doi:10.1097/CCE.0000000000000024

A New Test for the Detection of Direct Oral Anticoagulants (Rivaroxaban and Apixaban) in the Emergency Room Setting

Crit Care Explor. 2019 Aug 20;1(8):e0024. doi: 10.1097/CCE.0000000000000024. eCollection 2019 Aug.

Authors

Affiliations

¹ Division of Comparative Medicine, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA.
² BioMEMS Resource Center, Department of Surgery, Massachusetts General Hospital, Boston, MA.
³ Department of Pathology, Massachusetts General Hospital, Boston, MA.
⁴ Department of Biostatistics, Massachusetts General Hospital, Boston, MA.
⁵ Department of Cardiology, Massachusetts General Hospital, Boston, MA.
⁶ Advanced Tissue Resource Center, Harvard NeuroDiscovery Center, MGH, Boston, MA.

Abstract

Determining whether a patient has taken a direct oral anticoagulant (DOAC) is critical during the periprocedural and preoperative period in the emergency department. However, the inaccessibility of complete medical records, along with the generally inconsistent sensitivity of conventional coagulation tests to these drugs, complicates clinical decision making and puts patients at risk of uncontrollable bleeding. In this study, we evaluate the utility of inhibitor-II-X (i-II-X), a novel, microfluidics-based diagnostic assay for the detection and identification of Factor Xa inhibitors (FXa-Is) in an acute care setting.

Design: First-in-human, 91-patient, single-center retrospective pilot study.

Setting: Emergency room.

Patients: Adult patients admitted into the emergency department, which received any clinician-ordered coagulation test requiring a 3.2% buffered sodium citrate blood collection tube.

Interventions: None.

Measurements and main results: Plasma samples from patients admitted to the emergency department were screened for the use of FXa-Is, including apixaban and rivaroxaban, within the past 24 hours using our new i-II-X microfluidic test. i-II-X results were then compared with results from conventional coagulation tests, including prothrombin time (PT) and international normalized ratio (INR), which were ordered by treating clinicians, and an anti-Xa assay for rivaroxaban. The i-II-X test detected DOACs in samples collected from the emergency department with 95.20% sensitivity and 100.00% specificity. Unlike PT and INR, i-II-X reliably identified patients who had prolonged clotting times secondary to the presence of a FXa-I.

Conclusions: The i-II-X test overcomes the limitations of currently available coagulation tests and could be a useful tool by which to routinely screen patients for DOACs in emergency and critical care settings. Our new diagnostic approach is particularly relevant in clinical situations where medical records may be unavailable, or where precautions need to be taken prior to invasive interventions, such as specific reversal agent administration.

Keywords: anticoagulation; apixaban; coagulation; diagnostic; emergency; rivaroxaban.

Abstract

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