Therapeutic drug monitoring of selected direct oral anticoagulants

Direct oral anticoagulants (DOACs) describe a group of drugs that have emerged over the last decade, which are active against either activated factor II (or thrombin; IIa) or activated factor X (Xa). These drugs do not require routine therapeutic monitoring since they were developed and approved for use at fixed doses according to various approved clinical indications. Nevertheless, there may be times in which measurement of plasma levels may be clinically useful. There are laboratory-based assays to quantify their level. However, it is important to mention that DOACs also affect many laboratory tests including coagulation tests. This chapter provides an overview of assay methods that may be useful for this purpose.