A fundamental requirement for achieving continuity of care is the seamless sharing of multi-clinical information. Several different technological approaches can be followed to enable the sharing of health record segments. In all cases interoperability between systems is a prerequisite and this requires presently a major technological challenge. Interoperability can be achieved either through messages or through a more advanced approach based on a federation of autonomous systems. Message based integration is centered mainly on the exchange of HL7 and DICOM messages for achieving the functional integration of clinical information systems (CIS) at institutional or regional level. The federated approach is principally used for facilitating the virtual view of the Integrated Electronic Health Record (I-EHR), without having to replicate unnecessary information.

Within the context of HYGEIAnet, which is the regional health telematics network of Crete, both approaches have been utilized for providing end users with seamless access to clinical information. Both are based on an open architecture, which provides the framework for the reuse of standardized common components and public interfaces. This work presents the experiences related to the implementation of “messaging” and ‘federating” in HYGEIAnet, which are used complementary to each other. A comparison of the two parallel approaches, together with their strengths and weaknesses is described, and evaluation is given from the technological as well as the end users’ perspective. Emphasis is given on the technological challenges in developing open, component-based information infrastructure to support integrated service delivery.