FHIR ValueSet/$validate-code membership check - OMOPHub.com API

Overview

Validates whether a code is a member of an implicit ValueSet. EHRbase uses this during composition validation to check if a submitted code falls within the allowed set for a template field. Supports the same ValueSet URL patterns as $expand.

FHIR clients typically call ValueSet search first as a preflight check to confirm the server supports the target ValueSet, then call $validate-code (or $expand) for the actual membership test. The two endpoints are independent - you can call $validate-code directly without the preflight if you already know the URL is supported.

Supported Patterns

All codes in a code system

curl "https://fhir.omophub.com/fhir/r4/ValueSet/\$validate-code?\
url=http://snomed.info/sct?fhir_vs&\
system=http://snomed.info/sct&code=44054006" \
  -H "Authorization: Bearer YOUR_API_KEY"

Is SNOMED code 44054006 valid? (Yes, if it exists in the SNOMED vocabulary.)

Descendants of a concept (is-a filter)

curl "https://fhir.omophub.com/fhir/r4/ValueSet/\$validate-code?\
url=http://snomed.info/sct?fhir_vs=isa/73211009&\
system=http://snomed.info/sct&code=44054006" \
  -H "Authorization: Bearer YOUR_API_KEY"

Is “Type 2 diabetes mellitus” (44054006) a descendant of “Diabetes mellitus” (73211009)? (Yes.)

Parameters

Parameter	Type	Required	Description
`url`	uri	Yes	Implicit ValueSet URL (e.g., `http://snomed.info/sct?fhir_vs` or `http://snomed.info/sct?fhir_vs=isa/73211009`)
`system`	uri	No	Code system URI of the code being validated (defaults to the ValueSet system)
`code`	code	Yes	The code to validate
`display`	string	No	Expected display text to verify

Response (valid code)

{
  "resourceType": "Parameters",
  "parameter": [
    { "name": "result", "valueBoolean": true },
    { "name": "display", "valueString": "Type 2 diabetes mellitus" }
  ]
}

Response (not a member)

{
  "resourceType": "Parameters",
  "parameter": [
    { "name": "result", "valueBoolean": false },
    { "name": "message", "valueString": "Code '22298006' is not a member of the ValueSet (not a descendant of '73211009')." }
  ]
}

Response (display mismatch)

{
  "resourceType": "Parameters",
  "parameter": [
    { "name": "result", "valueBoolean": true },
    { "name": "display", "valueString": "Type 2 diabetes mellitus" },
    { "name": "message", "valueString": "Display mismatch: provided 'Diabetes type 2', actual 'Type 2 diabetes mellitus'." }
  ]
}

Errors

HTTP	Issue Code	Cause
400	`invalid`	Missing `url` or `code` parameter, invalid ValueSet URL, or unknown code system
404	`not-found`	ValueSet root concept not found