Here are the responses to our April, 2018 Quick Question, "How do you measure the oral direct thrombin inhibitor dabigatran?"
- Standard thrombin time: 7 votes, 8%
- Activated partial thromboplastin time (APTT , PTT ): 5 votes, 5%
- Chromogenic ecarin clotting time assay: 9 votes, 10%
- HEMOCLOT thrombin inhibitor assay (plasma-diluted thrombin time): 17 votes, 18%
- We don't measure dabigatran: 54 votes, 59%
Thanks to our 92 responders. No surprises here as the US FDA has not approved the ecarin chromogenic assay or the plasma-diluted thrombin time. Those of us who use these fully validated assays are offering them on a research use only (RUO) basis. The standard thrombin time works well to rule out dabigatran, as it is sensitive to the drug. A normal thrombin time is evidence there is no dabigatran in the patient's plasma. The PTT is suggested as a semiquantitative approach, however assay responses are reagent-dependent.
For a comprehensive discussion of anticoagulant management, see the editorial, Favaloro EJ. Anticoagulant therapy: present and future Semin Thromb Hemost 2015;41:109–12, which introduces an entire issue of Seminars in Thrombosis and Hemostasis dedicated to anticoagulant therapy management.
By the way, apologies for the phrasing of answer 3, it should have read "Ecarin chromogenic assay." There's no clotting involved!