DOAC-Stop in lupus anticoagulant testing: Direct oral anticoagulant interference removed in most samples

Abstract

Background: The use of direct oral anticoagulants (DOACs) is a convenient therapeutic option for patients at risk of thrombosis. DOACs interfere with clot-based testing for the identification of lupus anticoagulant antibodies (LACs) in patients with antiphospholipid syndrome (APS), a common cause of acquired thrombotic disease. Objectives: To evaluate a commercially available reagent DOAC-Stop for the removal of DOAC interference encountered in LAC testing. Patients/Methods: We collected a cohort of 73 test samples from patients on DOAC therapy identified at a large institutional coagulation laboratory from March to December 2019, along with samples from 40 LAC positive and negative control patients not on therapy. Samples were treated with DOAC-Stop and tested for anti-Xa activity and thrombin time for the removal of apixaban, rivaroxaban, argatroban, and dabigatran activity from patient samples. Treated and untreated samples were tested using the activated partial thromboplastin time, silica clotting time, and dilute Russell’s viper venom time to evaluate the reliability and utility of DOAC-Stop. Results: DOAC-Stop markedly reduced DOAC interference from test samples (P