This document discusses protocols for massive transfusion and bleeding. It defines massive bleeding and massive transfusion, and explores ways to predict which patients may experience massive bleeding through the use of predictive scores and clinical/biological parameters. Predictive scores discussed include TASH and ABC scores. The document recommends activating a massive transfusion protocol for trauma patients with an ABC score >2 and decreased clot firmness on viscoelastic tests, or for non-trauma patients transfused with ≥4 RBC within 1 hour. Clinical parameters that could activate a protocol include low SBP/high HR, coagulopathy signs, low temperature, anemia, and lactic acidosis.