FHIR Chat · findings by qualifiers · snomed

Stream: snomed

Topic: findings by qualifiers

Jose Costa Teixeira (Aug 31 2020 at 10:09):

Hi (and apologies if I'm not using the right terms):
Can I query a server for all findings that have a given qualifier? How?
The case at hand: I want to see all findings that have a qualifier "Perinatal" or "Neonatal"

Cora Drenkhahn (Aug 31 2020 at 13:32):

If I understand this correctly you'll probably need to query using the Expression Constraint Language (ECL). Like this, you can limit your results to concepts that adhere to a given definition.
For your example the ECL expression would be something like this:

<< 404684003|Clinical finding| : << 246454002|Occurrence| = (
    (<< 371578004|Perinatal period| OR << 255407002|Neonatal|)
  )

Your server needs to be able to handle ECL but quite a few do.
Then, you can use the $expand operation to query an implicit ValueSet defined by ECL (see the last of the five possibilities).

Michael Lawley (Sep 03 2020 at 05:29):

You _should_ also be able to use ValueSet.compose.include.filter, since all properties should have a corresponding filter that supports the = and in operators (https://www.hl7.org/fhir/codesystem.html#filters). In this case, where you want to test << 255407002|Neonatal| it is unclear whether SNOMED's redefinition of the in operator to take a ValueSet URI as its parameter value applies, or whether the default comma-separated list of codes should be used.
If the ValueSet approach does apply, then you'd have

{
  "include": [{
    "system": "http://snomed.info/sct",
    "filter": [{
      "property": "concept",
      "op": "is-a",
      "value": "404684003"
    }, {
      "property": "246454002",
      "op": "in",
      "value": "http://snomed.info/sct?fhir_vs=isa/371578004"
    }]
  }, {
    "system": "http://snomed.info/sct",
    "filter": [{
      "property": "concept",
      "op": "is-a",
      "value": "404684003"
    }, {
      "property": "246454002",
      "op": "in",
      "value": "http://snomed.info/sct?fhir_vs=isa/255407002"
    }]
  }]
}

Note, this is quite the same semantics because it doesn't capture the descendants or self of << 246454002|Occurrence| but since Occurrence has no descendants this is not likely to be an issue.

Last updated: Apr 12 2022 at 19:14 UTC