Why isn't the HL7 standard using XML?

Question

I am new to HL7 and the first thing that came to my mind was, why isn't this format using XML instead? There are a handful of parsers and there are some serious inconsistencies among vendors.

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For those new to the health care software business I recommend this read http://www.interfaceware.com/hl7_version2x.html

Answer 1

HL7 version 3 is using XML. Earlier versions of HL7 are a health care specific derivative of a pipe delimited format (IIRC its called ER7, not sure though).

Theres nothing particularly wrong with the pipe delimited format. In many ways the newer XML variations are harder to use. It may be old, but for the most part it works and it is well understood.

Answer 2

Looks like v.2 was created in 1987 according to wikipedia: http://en.wikipedia.org/wiki/Health_Level_7

That's probably your answer.

Answer 3

Just an FYI... HL7 2.x is used far more in practice than the XML variant HL7 3.x.

2.x is simpler and faster to parse.

Answer 4

There are several versions of hl7 standards using the technology of its time:

• HL7 v2: Delimited text files
• HL7 v3: XML based format (on SOAP)
• HL7 FHIR: The newest format based on JSON and XML on REST that seem to have a bright future.

I wont list the advantages and disadvantages of them - all of them have their positive and negative things.

But if you start a new application and the parsing of the text file you offer issues - it's worth looking at FHIR.

Answer 5

There is an XML encoding for v2 messages, see "ANSI/HL7 V2 XML-2003 June 4, 2003: HL7 Version 2: XML Encoding Syntax Release 1", although I must warn you, it isn't pretty.