FHIR Chat · Using LOINC answer lists · implementers

Stream: implementers

Topic: Using LOINC answer lists

Chris Wand (Dec 20 2016 at 15:16):

I have some question about using LOINC answer lists as ValueSets (as documented in https://www.hl7.org/fhir/loinc.html#alist):

1) It seems weird to be using bogus urls (i.e. urls that result in 404s from loinc.org) as identifiers. If you weren't already aware of this convention, it would be pretty hard to figure out what was being referenced here.

2) Some implementations seem to regard these urls as invalid. (For example http://fhirtest.uhn.ca/ rejects these because it's expecting to see ValueSet in the url of a valid ValueSet)

James Agnew (Dec 20 2016 at 16:20):

@Chris Wand Ooh interesting.. Don't suppose you have an example you are trying to validate that you could send my way? That sounds like a good unit test in the making.

Chris Wand (Dec 20 2016 at 18:09):

A simple version of what I was trying to validate would be:

{
  "resourceType": "Questionnaire",
  "url": "http://some.example.url",
  "status": "draft",
  "subjectType": [
    "Patient"
  ],
  "item": [
    {
      "linkId": "example-question",
      "text": "Is the sky blue?",
      "type": "choice",
      "options": {
        "reference": "http://loinc.org/vs/LL3044-6"
      }
    }
  ]
}

Chris Wand (Dec 20 2016 at 18:11):

Also, @James Agnew did you just change the behavior here? Looks like it's now adding information-level issues to the response, rather than failing validation. (Or it could be that I was just misreading the response page earlier and it was never failing validation)

James Agnew (Dec 20 2016 at 20:18):

I updated the server to the latest validator yesterday, so yeah it's quite possible that behaviour has changed.

That said, looking at your example I don't think that is valid. That particular field questionnaire is a FHIR reference so it is expected to be resolvable. On the other hand the URL you listed is a canonical URL so it can only be used in places where a valueset uri is allowed (not a valueset reference)

Probably the only valid way to do what you're trying to do is to either find a resolvable URL which can be used to load that ValueSet, or create your own ValueSet and host it somewhere, then import the LOINC valueset into it.

Happy to be corrected if someone else here knows better than I do, but I think that's the correct answer here.

Grahame Grieve (Dec 20 2016 at 20:24):

@James Agnew in STU3, you're not right about canonical URLs anymore. They are allowed in references, though literal access most not resolve to a different resource than if you treated it as canonical

Grahame Grieve (Dec 20 2016 at 20:24):

@Chris Wand LOINC are working on getting all these URLs supported, but it's work in progress.

James Agnew (Dec 20 2016 at 20:30):

ahh i didn't know that change had gone through.

Time to update HAPI's validation code I guess.. :)

Last updated: Apr 12 2022 at 19:14 UTC