Health informatics Standards in general are discussed on FEM WIKI page 'Health Informatics Standards - general introduction'. Two other related pages focus on standard content and various other health informatics standards. This page is focusing on standardising systems and processes.

System standards are aimed at reusable structures - sometimes they are called model standards. These standards are very useful in building platform neutral, vendor neutral system specifications, in planning and implementing systems with standard functionalities for different organizations. Among the two families of process standards (describing processes within a system or describing processes coupling, connecting systems), the second variation, focusing on communication, messaging among systems is much more widely used and applied.

Regarding the structure / model oriented system standards different approaches cover different areas, a good comprehensive example is the family of (second generation) HISA standards: Health informatics - Service architecture - Part 1: Enterprise viewpoint - Part 2: Information viewpoint  - Part 3: Computational viewpoint. (ISO 12967-1,2,3:2009). Some early standards in this domain are rather high level models. An example is Medical Informatics - Healthcare Information Framework (HIF), ENV 12443:1999, or HISA, generation 1, the Healthcare Information System Architecture. These high level standards-for-standards on one hand initiated further, more detailed standard developments, on the other were used directly as design, planning blueprints. Another approach tries to standardize system functions, like the 'Electronic Health Record-System Functional Model (ISO 10781:2009)', coming from the HL7 family.

It is important to note the existence of a series of model standards that conceptually connect the separately discussed content standards ( see FemWiki entry 'Health Informatics Standards - Standard Content (code systems, nomenclatures and classifications)) and the here mentioned system model standards. These are the (health) data model standards. Probably the most important standards from future public health perspective are the electronic health record architecture standards, defining the data models, wherefrom data for various public health purposes are to be extracted. An example is the already mentioned EN 13606-1.4:2007 Health informatics - Electronic health record communication standard EHCRA. Other examples are e.g. the family of Patient healthcard data series EN ISO 21549-1...8.

Regarding the process oriented standards, as mentioned above the messaging standards are widely used due to the industrial pressure to provide shared platforms for intersystem communication. Again there are two levels (of general and specific) message standards to be distinguished. Example for the general message standards is the Health Level Seven Version 2.5: An application protocol for electronic data exchange in healthcare environments (ISO/HL7 27931) . HL7 2.x standards are widely used in the hospital world to exchange data among hospital information system components.  Example for a specific, domain related standard is e.g. the family of blood transfusion related messages standards, ENV 13730, Blood transfusion related messages , Part 1: Subject of care related messages, Part 2: Production related messages (BTR-PROD).

A third type of communication - messaging standards are the wide family of system <-> device communication standards, describing a how - to approach for connecting specific medical devices to information systems. An example here is the family Health informatics -- Point-of-care medical device communication standards, the ISO/IEEE 11073 series, dealing with a wide variety of devices from thermometers, weighing scales, glucose meters to computer assisted electrocardiography and beyond.

References

Here is a comprehensive list of world standards (ISO TC 215): Standards catalogue,
Here is home page of CEN TC 251: TC 251 link
here is the link to the published standards.
Another list shows the CEN TC 251 standards in development.