Direct oral anticoagulants: does one dose fit all? Why, when and how testing

Direct oral anticoagulants (DOAC) are commonly prescribed using fixed-dose regimens, based on the assumption of predictable pharmacokinetics and a favorable balance between efficacy and safety. As a result, laboratory assessment is often considered unnecessary in patients receiving DOAC. However, increasing evidence from clinical trials and real-world studies challenges this “one-dose-fits-all” paradigm, demonstrating marked interindividual variability in drug exposure. Importantly, extreme plasma concentrations have been associated with an increased risk of thrombotic events or bleeding complications. This article revisits the role of the clinical laboratory in the management of patients treated with DOAC, clearly distinguishing routine dose adjustment from targeted measurement in selected clinical scenarios. It discusses situations in which laboratory testing may meaningfully support clinical decision-making, as well as practical considerations regarding DOAC measurement and their interference with commonly used hemostatic assays. Overall, a more nuanced, patient-centered use of laboratory testing may improve the safety and effectiveness of DOAC therapy.