A single test to assay warfarin, dabigatran, rivaroxaban, apixaban, unfractionated heparin and enoxaparin in plasma.
J Thromb Haemost. 2016 Feb 29;
Authors: Letertre LR, Gudmundsdottir BR, Francis CW, Gosselin RC, Skeppholm M, Malmstrom RE, Moll S, Hawes E, Francart S, Onundarson PT
BACKGROUND: Assaying anticoagulants is usefulin emergency situations or prior to surgery. Different specific assays are currently needed depending on anticoagulant.
OBJECTIVES: We hypothesized that levels of warfarin, dabigatran, rivaroxaban, apixaban and heparins could be measured with the dilute prothrombin time (dPT) and dilute Fiix-PT (dFiix-PT), using highly diluted thromboplastin (TP). The latter test is affected only by reduced levels of active factors II and X but corrects test plasma for other deficiencies METHODS: Increasing TP dilutions were used to identify suitable dilutions to measure dabigatran, rivaroxaban, apixaban, unfractionated heparin and enoxaparin. Calibrators containing known amounts of direct oral anticoagulants (DOACs) were used to make standard curves. Citrated plasma samples were obtained from patients taking warfarin or DOACs with known drug concentrations as determined by specific assays.
RESULTS: The dFiix-PT at a TP dilution of 1:1156 could be used to measure all of the drugs tested at therapeutic concentrations except for fondaparinux. The dPT achieved the same, but required two TP dilutions (1:750 and 1:300). Warfarin effect could be assessed using dFiix-PT at 1:1156 with a PT ratio identical to the INR. Six different TPs yielded similar results, but two were less sensitive. Dabigatran, rivaroxaban and apixaban could be accurately measured in patient samples using both dilute PT assays but a better correlation was consistently observed between the dFiix-PT and specific assays than with the dPT.
CONCLUSION: The dFiix-PT using a single dilution of TP may be suitable to assess the anticoagulant effect of warfarin, dabigatran, rivaroxaban, apixaban, heparin and enoxaparin. This article is protected by copyright. All rights reserved.
PMID: 26924677 [PubMed - as supplied by publisher]