Abstract Number: PB0669
Meeting: ISTH 2020 Congress
Background: dRVVT (dilute Russell’s Viper Venom Time) is a popular assay for detection of lupus anticoagulants (LA), a marker of thrombophilia. Anticoagulant-free plasma samples are ideal for LA testing but not always feasible because anticoagulant therapy is a common thrombosis treatment. Anticoagulant interference may impact dRVVT results, affecting diagnosis.
Aims: We evaluated effects of numerous anticoagulants and common interferents on four commercial dRVVT assays to compare assay-specific impacts to LA diagnosis.
Methods: Precision BioLogic Inc. (PBI) dRVVT screening and confirmatory assays were performed on three analyzers – Stago Evolution (mechanical), IL ACL-TOP (optical) and Siemens BCS XP (optical) – and compared with the respective manufacturer’s dRVVT assay. Plasma samples spiked with matrix blank or interferent were tested in quintuplicate according to the manufacturer’s test application. Interferents were: Heparins (UFH, LMWH, Enoxaparin; 1 U/mL), Argatroban 1.5 µg/mL, Fondaparinux 1.25 µg/mL, Rivaroxaban 0.4 µg/mL and VKA plasma from patients on warfarin (INR< 3, N=10). HIL spiked samples (Hemoglobin 250 mg/dL, Bilirubin 2.5 mg/dL, Intralipid ~500 mg/dL) were also tested.
Results: Heparins and HIL did not affect results. However, both optical analyzers failed to detect clots in intralipid-spiked samples. FIIa inhibitor argatroban had no diagnostic impact, except it produced errors with IL ACL TOP, precluding results. FXa inhibitor fondaparinux did not affect results, but rivaroxaban caused false positive results with Siemens, Stago and IL reagents while PBI diagnostic results were unaffected. VKA (warfarin) had a similar impact; using Siemens, Stago and IL reagents, false positive results were observed in some samples while PBI results were correctly identified as LA negative.
Conclusions: Due to differences in test systems, different influences by DOACs and warfarin on dRVVT results can be expected. Notably, samples containing rivaroxaban or VKA would be correctly diagnosed with PBI reagents but might be incorrectly diagnosed false positive with Siemens, Stago or IL dRVVT reagents.
To cite this abstract in AMA style:Sadeghi-Khomami A, Lamont D, Boylan M, Clarke R, Kesavan N, Douglas C, Black K. Effects of Anticoagulants and Common Interfering Substances on Four Commercially Available dRVVT Assays [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/effects-of-anticoagulants-and-common-interfering-substances-on-four-commercially-available-drvvt-assays/. Accessed October 20, 2020.
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