Dave McGlasson, hemostasis researcher at Wilford Hall USAF Medical Center in San Antonio, is engaged in a large-scale dabigatran measurement project. He reports that a prominent Midwestern medical center uses 45–95 ng/mL as their therapeutic range, using the plasma-diluted thrombin time (DTT, Hemoclot® direct thrombin inhibitor). In the article in Europace (2013) 15, 625–51 (posted May 9, 2013 on Fritsma Factor)the authors, using the DTT, say that bleeding is documented when the result is ≥ 200 ng/mL (~65 seconds) at trough. Trough (nadir) is defined as just before the next dosage, or 12 hours after the previous dose. In Mr. McGlasson’s study the range on subjects who have their blood drawn at different times of the day (convenience sample) is ~0–700 ng/mL using the DTT. Results are similar when measuring with the Ecarin chromogenic assay, prothrombinase-induced clotting time (PiCT) assay and the partial thromboplastin time (APTT, PTT). Mr. McGlasson asks, we are now working on establishing a therapeutic range, what are other sites seeing? Please provide your answer in the comments section below.