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Comment by drstewart | Hacker News Reader

What about HL7?

HL7 is a data interchange format, not a data storage format. You can't code to that spec the way you can to DICOM. EHRcon and CDA are jokes.

And, of course, the vendors who stitch together siloed datasets from proprietary vendors make a killing. So that's yet another group who loves the status quo.

HL7 CDA R2 works pretty well as a data storage format for certain types of medical records.

HL7 is often characterized as a "70% standard," meaning that instead of getting complete agreement from vendors, they decided to standardize most of it. (HL7 3.0 is an 80% standard, but no one really uses HL7 3.0, at least not in the U.S.)

Think of HL7 as a language with many dialects. As a result there are whole industries for translating feeds both within hospitals (integration engines) and between institutions (RHIO/HIEs).

As the saying goes:

"Once you've seen one HL7 message, you've seen one HL7 message".

it's delimited by pipes... i mean, it is a standard, but it's far from ideal.

Technically it's delimited by whatever character is decided to be the delimiter, which is even better :)

Having said that, it still seems to get data between all sorts of systems in the hospital.

In my experience with HL7 it's a standard, but every single system you talk to you need to write custom code to handle them, because everyone talks the "standard" a bit differently.

[edit] and as for the XML v3, nobody uses it. Nobody.

Absolutely (for both points). I found HL7v2 to be more of a 'standard of communication of data' as opposed to a 'standard of data'. A lot of the work I did in my last job was dealing with these differences... I think the best investment of my time was the code I wrote to more easily interact with the messages, just to help alleviate those differences.

All in all, very fun times :)

That I think is the key distinction: HL7 works okay for a group of tightly coupled systems, usually internal to a single organization. The biggest problems today are with data interchange between providers, networks of providers, 3rd party vendors (cloud based or whatever) and the like. The finance and insurance industry have, I think, figured this out. Healthcare has not.

That's a good point and to be honest, I didn't deal much with things outside of the hospital itself (I mainly worked in the ADT 'sphere') but I could see how the 3rd party stuff could get hairy... especially if they're trying to deal with different message formats within the same facility.

lol, yeah, im sure it works. it isn't json tho...

you could also say Cache (it's a post-relational database... whatever that means) is a standard database used in medical systems, but it sure isn't a postgres.

It is an object database which was all the rage back in 1996-ish. I had to use it outside of the medical market once and the sales manager was shocked!

HL7 v3 is xml: https://en.wikipedia.org/wiki/Health_Level_7#HL7_version_3

HL7 V2 actually defines two standard encodings: ER7 and XML. They are both logically equivalent. The ER7 encoding is similar to old EDI standards and typically uses the '|' character as the field delimiter (although certain other characters can be used instead). Unfortunately the XML encoding is poorly supported and most applications use the ER7 encoding.

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