HL7

HL7 is the Health-Level-Seven protocol. It is a specialized set of communications rules on the Application layer (the seventh level) of the TCP/IP Network Stack, focused on Healthcare specific information to be sent between computers providing interchange of health application data.

The typical HL7 message contains several HL7 segments. Each segment (line of text) starts with a header consisting of several letters, such as MSH or PID . There are one or more segments making up a message, and the segments are made up of more than one composite. Typically segments are seperated by carriage returns ($C(13) or hex 0D ), and composites are seperated by "pipe" or "bar" symbols (ie: | ). The composite seperator is defined in the MSH segment, so it may actually be changed if necessary.