The effect of dabigatran on haemostasis tests: a comprehensive assessment using in vitro and ex vivo samples

Summary: The new direct oral anticoagulants (DOACS) dabigatran, rivaroxaban, apixaban and edoxaban provide alternatives to warfarin for treatment and prevention of atrial fibrillation and venous thromboembolic disease in various settings. These have been developed as not requiring laboratory monitoring; however, under certain clinical situations, including recent haemorrhage/thrombosis, emergency surgical procedures, testing may be indicated. The aim of this study was to assess findings of haemostasis laboratory tests for one of the DOACs, dabigatran (Pradaxa), tested across a wide range of laboratory assays. Laboratories (n = 72) enrolled in the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) Haematology program were sent set(s) of seven dabigatran spiked plasma samples covering the concentration 0–800 ng/mL. Also, 30 ex vivo patient samples under therapy with dabigatran were assessed. Prothrombin time and activated partial thromboplastin time assays showed some sensitivity to dabigatran; however, a normal result could not inform on drug exclusion. The thrombin time (TT) was very sensitive to dabigatran, and a normal TT could generally be used for drug exclusion. More specialised assays such as the Hemoclot, a direct thrombin inhibition assay, and in-house dilute TT methods, showed good reproducibility and concordance with expected drug levels assessed by mass spectrometry and were effective to quantify drug levels. Dabigatran also a...
Source: Pathology - Category: Pathology Tags: Haematology Source Type: research