The effect of DOAC‐Stop® on several oral and parenteral anticoagulants

Dear Editors, DOACStop® is a hydrophobic binding agent, containing activated charcoal, which can absorb the direct oral anticoagulants (DOACs) from plasma samples in vitro.1 It neutralized the effect of apixaban, edoxaban, rivaroxaban and dabigatran on routine coagulation assays, such as activated partial thromboplastin time (aPTT) and prothrombin time (PT)/international normalized ratio (INR).13 It has been proposed that DOACStop® not only can identify which samples with prolonged coagulation assay results actually contain the DOACs,1 but might also aid in estimating the DOAC concentration by calculating a “correction ratio” of aPTT before/after DOACStop® treatment, if the reagents are adequately sensitive to the DOACs.4 DOACStop® reduced the rate of false positive lupus anticoagulant assays,5,6 thus can allow to perform thrombophilia testing without stopping DOAC treatment. A study performed with the thrombin generation assay showed that DOACStop® eliminated the interference of dabigatran with the calibrators7 and there are some reports that other low molecular weight anticoagulants (eg argatroban and lepirudin) were extracted by DOACStop®.2 However, it has been suggested that DOACStop® might prolong the aPTT results,8 while in another study the normal plasma treated with DOACStop® showed hypercoagulability on the thrombin generation assay, compared to the same untreated plasma.7 The aim of this study was to explore the effect of