Update on laboratory testing and hemostasis assessment in patients receiving direct oral anticoagulants (DOACs)

Abstract

Direct oral anticoagulants (DOACs) have been established and already registered worldwide for clinical use. Contrary to vitamin K antagonists, their mode of action is based on the direct inhibition of the single coagulation enzymes factor Xa or IIa. Even though the DOACs do not require routine laboratory monitoring, hemostasis assessment and laboratory testing using calibrated assays may become helpful in several clinical situations to help patient management and improve outcomes. Laboratory tests of hemostasis, such as the screening tests prothrombin time (PT/INR) and activated partial thromboplastin time (APTT) or various functional coagulation assays involving generation of factor Xa or IIa for their endpoints, can be negatively influenced by the presence of the anticoagulant in the test sample. This interference has been well documented for rivaroxaban, apixaban and dabigatran and is most prominent during the first hours after intake of the respective agent. Thus, potential influence of DOACs has always to be considered when interpreting abnormal functional coagulation assays. The objective of this review was to update systematically evidence regarding usefulness and pitfalls in laboratory assessment and testing of the anticoagulant effects of DOACs.