Dabigatran and laboratory tests [Dabigatran e analisi di laboratorio]

New oral anticoagulants (i.e., dabigatran, rivaroxaban, apixaban) are now available. In using these drugs, routine monitoring of laboratory coagulation tests is not recommended. In some clinical conditions, however, a laboratory evaluation of hemostatic balance may be useful. Tests suggested for laboratory monitoring of dabigatran treatment are thrombin time on undiluted (TT) or diluted (dTT) plasma and ecarin clotting time. On 30 patients taking dabigatran for non valvular atrial fibrillation, we assayed dabigatran levels by dTT, also performing prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and TT. In patients taking dabigatran etexilate 110 mg bis in die and 150 mg bis in die, dTT mean results (10th-90th percentile) were 97 (32-152) and 94 (33-189) μg/L, respectively. In dTT range from 13 to 60 μg/L and >60 μg/L, we obtained 27% and 58% prolonged PT, 64% and 95% prolonged APTT, and 100% and 100% prolonged TT, respectively, showing that for dabigatran TT is a useful screening test.