Figure. Interaction diagram shows how patient information flows from the registration system to interested endpoint systems by means of ADT messages. A01, A04, A05, A11, and A38 represent the specific trigger events that cause the transmission of messages: admission, registration, preadmission, admission or registration cancellation, and preadmission cancellation. Each of these events triggers the generation of an event-specific message to the Order Placer, department, and master patient index (MPI) systems.