When used in fixed doses for stroke prevention in atrial fibrillation (SPAF) and for the prevention and treatment of venous thromboembolism (VTE), direct oral anticoagulants (DOACs), including apixaban, dabigatran, edoxaban and rivaroxaban, have improved risk-benefit profiles and convenience as compared to vitamin K antagonists (VKAs). Accordingly, current guidelines recommend DOACs over VKAs for these indications and advocate against routine laboratory monitoring of DOACs [1–3]. However, there are clinical circumstances in which measurement of drug concentrations may guide medical management of select patients receiving DOACs (Table 1).
