FHIR CodeSystem/$subsumes for concept hierarchy

Overview

Tests whether concept A subsumes (is an ancestor of) concept B, or vice versa. Used for hierarchy-aware code validation and clinical decision support. Supports both type-level and instance-level invocation.

Request

# Does "Diabetes mellitus" subsume "Type 2 diabetes mellitus"?
curl "https://fhir.omophub.com/fhir/r4/CodeSystem/\$subsumes?\
codeA=73211009&codeB=44054006&system=http://snomed.info/sct" \
  -H "Authorization: Bearer YOUR_API_KEY"

By OMOP concept ID

curl "https://fhir.omophub.com/fhir/r4/CodeSystem/\$subsumes?\
codeA=201820&codeB=201826&system=https://fhir-terminology.ohdsi.org" \
  -H "Authorization: Bearer YOUR_API_KEY"

Instance-level

curl "https://fhir.omophub.com/fhir/r4/CodeSystem/omop-v20260227/\$subsumes?\
codeA=201820&codeB=201826" \
  -H "Authorization: Bearer YOUR_API_KEY"

Parameters

Parameter	Type	Required	Description
`codeA`	code	Yes	First concept code
`codeB`	code	Yes	Second concept code
`system`	uri	Yes (type-level)	Code system URI

Response

{
  "resourceType": "Parameters",
  "parameter": [
    { "name": "outcome", "valueCode": "subsumes" }
  ]
}

Possible Outcomes

Outcome	Meaning
`equivalent`	A and B are the same concept
`subsumes`	A is an ancestor of B (A subsumes B)
`subsumed-by`	A is a descendant of B (B subsumes A)
`not-subsumed`	No hierarchical relationship between A and B

Examples

# A subsumes B (Diabetes mellitus → Type 2 DM)
# → outcome: subsumes

# Reverse (Type 2 DM → Diabetes mellitus)
# → outcome: subsumed-by

# Same concept
# → outcome: equivalent

# Unrelated concepts (Type 2 DM vs Myocardial infarction)
# → outcome: not-subsumed

Errors

HTTP	Issue Code	Cause
400	`invalid`	Missing `codeA`, `codeB`, or `system` parameter
404	`not-found`	Code not found in the specified code system

FHIR ValueSet/$validate-code membership check FHIR CodeSystem/$find-matches for property search

​Overview

​Request

​By OMOP concept ID

​Instance-level

​Parameters

​Response

​Possible Outcomes

​Examples

​Errors