Rivaroxaban: Anti-FXa activity PT and aPTT modified according to the reagent (PT more sensitive) Apixaban: Anti-FXa activity PT and aPTT not really prolonged Dabigatran: Ecarin clotting time, Haemoclott or anti-IIa PT, aPTT and TT modified according to the reagent (aPTT more sensitive) Ref. MM Samama et al Clin Chem Lab Med 2011;49,761