RESUMEN
BACKGROUND: Monitoring non-vitamin K antagonist oral anticoagulants (NOAC) is usually not necessary; however, in some patients it may prove beneficial. OBJECTIVES: Patient subgroups who may profit from monitoring were identified, and methods of monitoring (including assessment of which coagulation parameters are affected by NOAC) are described. MATERIALS AND METHODS: We searched the PubMed database for each of the search terms, "NOAC", "DOAC", "rivaroxaban", "dabigatran", and "apixaban", in combination with one of the terms, "monitoring", "measurement", "measuring", or "assessment". The results were compiled and reviewed. RESULTS: Monitoring is most advantageous in emergency cases with severe bleeding where drug activity needs to be assessed. It can also help in deciding for or against lysis therapy after acute stroke in patients taking NOAC. Furthermore, it can also identify compliance problems and help in planning periprocedural management. There are quantitative measurement methods which measure plasma concentrations exactly and qualitative methods which only allow for a rough estimate or a general confirmation of drug activity. Recommended quantitative measurement methods are diluted thrombin time for dabigatran, and anti-factor Xa activity (calibrated) for rivaroxaban and apixaban. CONCLUSIONS: Several patient subgroups may profit from monitoring of NOAC plasma concentration. One should, however, take several issues into consideration before measurements, such as the objective of each individual measurement, possible consequences (e. g., dose adjustment), and which measurement method to pick.