Abstract
         
         When data are transmitted between electronic patient record (EPR) systems, we can
            distinguish several tasks. One task is the definition of structure and semantic content
            of the data in a message structure. Another task is the mapping of the sending EPR’s
            structure to this message structure. A third task is the mapping of the message structure
            to the receiving EPR’s structure. We describe an approach, which distinguishes clearly
            between these different tasks and activities. Using this approach we have implemented
            a data transfer procedure between a cancer registry application and a middleware for
            healthcare information systems. Our experience showed that the proposed systematic
            approach helped identify problems for data transfer in an early design phase. It also
            allowed us to limit modifications of the data exchange procedure to certain tasks
            or activities when one of the EPR applications was updated. In the end, we could even
            exchange the underlying message format without having to reimplement the complete
            interface.
         
         Keywords
Electronic Patient Record - Standards - Communication