There are different versions of HL7. Currently the common one is some line and character delimited format, HL7 v2. {OBX,ORC,etc.} |data|||more data|number|||id

There are different versions of HL7. Currently the common one is some line and character delimited format, HL7 v2. {OBX,ORC,etc.} |data|||more data|number|||identifier| Which is basically a member of the multimap with the first word as the key, with an indexed map of text. It's not really a standard like HTML, at least no EMRs, interface systems, instruments, and so on abide by them. So, whenever systems hook up, there has to be setup / build to map what text means what to each other--although the positions are generally agreed upon. When interfacing systems together, there is both a legal and a technical cost that must be dealt with. With highly configurable systems on both ends, figuring out who's terms / categories equate on the other side and back is not an easy task and most organizations hesitate to go through with it unless necessary. The tools are there, it's just that when everyone customizes their own universe, it's unlikely to work out of the box. You can stick a german and a guy from holland together in the same room, they might have some shared words, but whether they can hold a coherent conversation in their native tongue is a different matter.