Hemostasis and transfusion medicine are two parallel disciplines that come together when a patient experiences acute and brisk bleeding and transfusion is considered as a potential option. Understanding how to evaluate hemostasis clinically and in the laboratory is essential for rapid and cost-effective use of resources including transfusion of blood products. In this session, the speakers will review the pathophysiology of a variety of bleeding conditions and when and how commonly available laboratory tests should be used to reach a diagnosis. In addition, case studies of the proper use of plasma, platelets and factor concentrates will be discussed through the use of simple algorithms.