Martin Kertys

Direct oral anticoagulants are widely used in many indications to prevent thromboembolic events. Routine therapeutic monitoring is not required; however, there is increasing evidence suggesting the benefit of plasma level measurement in some situations. In addition, laboratory monitoring might help improve patient and drug non‐compliance and thus individualize therapy. In the present study, we developed a sensitive and high throughput ultra‐high‐performance liquid chromatography‐tandem mass spectrometry method for simultaneous quantification of apixaban, dabigatran, edoxaban, and rivaroxaban in human plasma. A one‐step extraction procedure in 96‐well formate for phospholipid and protein removal was used for sample pre‐treatment, and analytes were separated using gradient elution over 4.2 min. Analytes were detected on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode. The method was validated according to the European Medicine Agency guideline for the selectivity, linearity, and lower limit of detection, precision and accuracy, matrix effects, extraction recovery, carryover, dilution integrity, and stability over a concentration range of 3.0–1000 ng/ml for all analytes. The validated method was applied to real clinical samples of patients treated with one of the drugs. Therefore, we can conclude that our method is suitable for therapeutic drug monitoring of direct oral anticoagulants.