Bleeding time and volume after 14E11 administration. Mice treated with the anti-FXI antibody 14E11 (4 mg/kg subcutaneously) 30 minutes before tail cut show normal tail bleeding time (A) and volume (B), whereas APC (6 mg/kg subcutaneously) treatment significantly increases bleeding time compared with PBS vehicle-treated controls; n = 12 each. **P = .01 (log-rank test for right censored data). During experiments, mice were sedated with 5% isoflurane and immobilized for tail transection at 1.5-mm tail diameter. After transection, the tail was placed into a 1-mL microcentrifuge tube of room temperature water and time until bleeding cessation was recorded. The experiment was ended, and data were censored if bleeding continued beyond 30 minutes.