hemoglobin count 10.6 g/dl. Prothrombin time (PT) was 100% (normal range: 70%-100%), activated partial thromboplastin time (APTT) with normal plasma [ratio 1:1] was 1.24 (Normal range: 0.80-1.20). Her laboratory evaluation revealed an FXI level quantitated at 41%.A routine hematology consultation was obtained and a bleeding management strategy was established that was performing the surgical procedure with antifibrinolytic therapy with tranexamic acid (1 g twice a day, for 10 days), avoid nonsteroidal antiinflammatory and use of Factor XI concentrates (Hemoleven®, LFB) only if bleeding.The surgery was done without any problem, bleeding was about 200 mL and no transfusion was needed.The patient remained in the post-anaesthesia care unit for 80 minutes and then returned to her hospital room. She was discharged from the hospital the day after surgery. No adverse events have been reported. Case 2White French female patient, 33-years-old, 56 kg, 156 cm was scheduled for a tubal ligation. Vital signs (blood pressure, temperature, oxygen saturation and Glasgow coma score) were normal. His ASA physical status was 2, her treatment was Levothyroxine 75 µg. Past medical history found a hypothyroidism. Past surgical history consisted of two deliveries without complication, bilateral inguinal hernia, appendectomy, tonsillectomy without problem. A wisdom teeth extraction done in 2016 presented a hemorrhagic complication and laboratory evaluation found a factor