DOAC stop use in real life – a single centre validation study

Background: DOAC STOP (Haematex Research, Sydney) is an activated charcoal based agent that absorbs all commonly used direct oral anticoagulants (DOACS) from plasma, enabling assessment of underlying coagulation.1 There is limited data on the effect of DOAC STOP on less common factor assays and on true positive lupus anticoagulant (LA) tests.2 Method: A local validation study of DOAC STOP was undertaken at Sullivan Nicolaides central laboratory (Bowen Hills, Queensland). Efficacy in eliminating dabigatran and rivaroxaban was assessed by comparing anti-Xa assays and TCT pre and post DOAC STOP (n=7). Common coagulation assays, extended factor levels and prothrombotic screen were tested pre and post DOAC stop in normal samples (n=43). LA testing was performed pre and post DOAC STOP in patients with known LA positivity (n=10). Results: DOAC stop effectively removed dabigatran and rivaroxaban. There was no major difference (>10%) in any of the assays pre and post DOAC stop. All 10 samples with detectable LA remained detectable after treatment with DOAC STOP. Discussion: This is the first study reporting the stability of less common factor assays with DOAC STOP. Results suggest that DOAC STOP does not abolish detected LA results, therefore providing a valid method for detecting LA whilst on DOAC therapy.3 1.Exner T, Michalopoulos N, Pearce J, et al. Simple method for removing DOACs from plasma samples. Thromb Res 2018; 163: 117–22.2.De Kesel PM, Devreese KMJ. Direct oral anticoagulant adsorption: impact on lupus anticoagulant testing–Review of the literature and evaluation on spiked and patient samples. J Thromb Haemost 2020; 18: 2003–17.3.Favaloro EJ, Gilmore G, Arunachalam S, et al. Neutralising rivaroxaban induced interference in laboratory testing for lupus anticoagulant (LA): a comparative study using DOAC Stop and andexanet alfa. Thromb Res 2019; 180: 10–19.