The Health Level Seven (HL7) Standard applies to the electronic exchange of data in all healthcare environments. Within the context of healthcare messaging, the HL7 standard is primarily concerned with the data content of exchanges between healthcare applications, the sequence or interrelationships in the flow of messages and the communication of significant application level exceptions or error conditions.
The HL7 Version 3 messaging standard addresses the support for the Transmission Patterns as supported by HL7, including the identification of sending and receiving entities for an HL7 messaging interaction.
To implement HL7 Version 3 messaging, the Version 3 messaging standard specifies
- How messaging communications should be conducted.
- How to respond to exceptions or errors that are experienced by a generic messaging framework that is processing an HL7 messaging interaction.
- HL7 relies upon well-defined protocols at the lower layers for mechanisms that ensure correct and complete packaging and delivery of message content. The Transport Specifications (e.g. ebXML, Webservices, MLLP) address moving the message payload (the HL7 v3 composite message) from sender to receiver. The Abstract Transport Specification describes the overall HL7 communications architecture. You are referred to the Abstract Transport Specification as well as the various Transport Specifications for details.
Error handling within HL7 messaging is confined to reporting errors in message structure, semantic content or failure on the communication link with the receiving system. Other issues such as packet framing and transport integrity are addressed at lower layers of the OSI framework and are outside the scope of this Standard.
HL7 messages may be transmitted within a framework that allows for secure communications. The framework in use for a particular implementation can be referenced in one of the messaging profile identifiers included. HL7 itself does not mandate the use of any particular framework. The implementation of security capabilities is often dependent on the encoding technology (such as XML) and the Transport.