Abstract
Background: The effect of direct oral anticoagulants (DOAC) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa, is a well-known problem and can cause both false positive and negative results. In particular, the situation in patients who develop lupus anticoagulant (LA) antibodies is highly complex. To evaluate the effectiveness of DOAC therapy in lupus-positive patients, 31 samples were enrolled in this retrospective study. All patient samples were spiked with three types of DOAC (dabigatran, DABI; rivaroxaban, RIVA; and apixaban, API) in a concentration that significantly influenced the screening test for LA and thus can mask the presence of LA. Subsequently, the DOAC was always unbound by the DOAC-Stop procedure. DOAC levels before and after binding were determined by functional assays, followed by liquid chromatography coupled with mass spectrometry (LC-MS) analysis. Methods: The determination of DOAC levels was performed by direct thrombin assay and determination of anti-Xa activity with specific calibration as functional tests for DABI and xabans (API and RIVA). To determine concentration levels of API, DABI, and RIVA, our in-house LC-MS method was used. Results: The results of LA-positive samples show significant differences between functional tests and the LC-MS method both before and after DOAC binding. Conclusions: The acute findings of the presence of LA-type antibodies fundamentally affects the determination of DOAC by functional tests, and in this case, it is necessary to use LC-MS analysis to determine the true value. If patients treated with DOAC develop LA of medium and higher titers, we do not recommend checking DOAC levels with functional tests.
Highlights
Several publications have addressed the impact of lupus anticoagulant (LA) testing in patients treated with new direct oral anticoagulants (DOAC), who have progressively developed lupus anticoagulant antibodies
The results of individual direct anticoagulant levels were evaluated by each method, functional assays and liquid chromatography coupled with mass spectrometry (LC-MS) for individual anticoagulants and after the DOAC-Stop procedure, which removed 99% of the direct anticoagulant
The results of individual direct anticoagulant levels were evaluated by each method, functional assays and for individual anticoagulants
Summary
Several publications have addressed the impact of lupus anticoagulant (LA) testing in patients treated with new direct oral anticoagulants (DOAC), who have progressively developed lupus anticoagulant antibodies. Is it not affected by the presence of antibodies that interfere with the functional tests for determining DOAC levels?. Patients may develop LA secondary to the course of treatment for atrial fibrillation, the prevention of ischemic stroke and thromboembolic events. These patients, in whom DOAC levels need to be monitored in some situations, are the focus of our study. All patient samples were spiked with three types of DOAC (dabigatran, DABI; rivaroxaban, RIVA; and apixaban, API) in a concentration that significantly influenced the screening test for LA and can mask the presence of LA. Methods: The determination of DOAC levels was performed by direct thrombin assay and determination of anti-Xa activity with specific calibration as functional tests for DABI and xabans (API and RIVA). If patients treated with DOAC develop LA of medium and higher titers, we do not recommend checking DOAC levels with functional tests
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