LABORATORY TEST INTERPRETATION AND PATIENT MANAGEMENT : The effects of NOACs on laboratory coagulation tests are summarized in the Table . Effect of Dabigatran on Coagulation Tests: â¢ Dabigatran can potentially affect the PT/INR, aPTT and TCT but these tests should not be used to monitor the anticoagulant. effect of NOACs. â¢ Dabigatran has a peak effect 1-3 hours after oral intake and if testing is done within this time, it can lead to an elevated PT/INR,