Implementation of edoxaban anti-Xa activity assay in a hospital laboratory and evaluation of its analytical performance

Edoxaban is a direct oral anticoagulant available in Europe but not in France. Given the high tourist traffic in France, understanding the pharmacology of edoxaban and the availability of its laboratory testing seemed crucial in emergency situations. The aim of this work was to describe the methodology for measuring the anti-Xa activity of edoxaban, highlighting pre-analytical and analytical aspects, along with essential clinico-biological data for therapeutic guidance. The analysis was performed using the chromogenic method on the STAR-Max analyzer, with the STA®-Liquid ANTI-Xa kit (Diagnostica Stago®). Anti-Xa Edoxaban level measurement has a detection limit of 15 ng/mL, a quantification limit of 20 ng/mL and a linearity limit of 400 ng/mL. Repeatability, intermediate precision, accuracy, and measurement uncertainty studies were conducted to assess method performance, meeting quality requirements. The comparison between two STAR-Max® analyzers showed excellent results with linear regression and a low bias with good precision and no loss of dispersion regardless of edoxaban levels. In conclusion, although the measurement of edoxaban level may be rarely necessary in clinical practice, its implementation is straightforward. The availability of edoxaban in neighboring countries, underscores the importance of having its measurement available in hospital laboratories.