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A question has been raised about whether we should support multiple standards. The feeling of the community is that we would eventually like to support multiple standards that are deemed useful. For example, FHIR may be useful in the future for more advanced querying of the SHR data. This brings up the question of external-facing standards (the ones the users of the HIE use) and the internal-facing standards (the ones used between components of the HIE) should always be the same or if we can expect to do transformation between different standards. The feeling of the community has been that we should not do transformations between different standards and rather expose multiple standards interfaces both internally and externally if needed. the reason for this is that it can be complex mapping and transforming messages between formats. This does not mean that we will do no transformation of messages, merely, that the transformation that we expect will be needed are transformation of the base standards to a more con formant conformant form of that same base standards. For example, enriching a HL7 message to contain additional required patient information. 

Each of the above standards are described in more details detail below:

HL7 v2

Overview

HL7 v2 messages are very popular and are commonly used as a message exchange format. This standard has been around for a long time so it has a large number of freely available tools that developers can make use of. It consists of a large number of message types for many different use cases each with their own structure and defined syntax. For technical interoperability HL7v2 employs the MLLP protocol that build upon TCP sockets. HL7 v2 messages can be encoded in either the ER7 (pipes and bars) format or as XML. The XML format allows HL7 v2 to be used in more current day web services.

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