This Standard specifies a means for communicating part or all of the electronic health record (EHR) of one or more identified subjects of care between EHR systems, or between EHR systems and a centralised EHR data repository. It may also be used for EHR communication between an EHR system or repository and clinical applications or middleware components (such as decision support components) that need to access or provide EHR data, or as the representation of EHR data within a distributed (federated) record system. This International Standard will predominantly be used to support the direct care given to identifiable individuals, or to support population monitoring systems such as disease registries and public health surveillance. Uses of health records for other purposes such as teaching, clinical audit, administration and reporting, service management, research and epidemiology, which often require anonymisation or aggregation of individual records, are not the focus of this International Standard but such secondary uses might also find the standard useful. This Part 1 of the multipart series is an Information Viewpoint specification as defined by the Open Distributed Processing Reference model: Overview (ISO/IEC 10746-1). This International Standard is not intended to specify the internal architecture or database design of EHR systems.