Documentation Index
Fetch the complete documentation index at: https://docs.omophub.com/llms.txt
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Overview
Compares concepts between two OMOP vocabulary releases. Returns counts and details of added and deprecated concepts. This is an OMOPHub-exclusive operation with no FHIR standard equivalent.
Request
curl "https://fhir.omophub.com/fhir/r4/CodeSystem/\$diff?\
from=2025.2&to=2026.1&count=5" \
-H "Authorization: Bearer YOUR_API_KEY"
With vocabulary filter
curl "https://fhir.omophub.com/fhir/r4/CodeSystem/\$diff?\
from=2025.2&to=2026.1&system=http://snomed.info/sct&count=10" \
-H "Authorization: Bearer YOUR_API_KEY"
Parameters
| Parameter | Type | Required | Description |
|---|
from | string | Yes | Old vocabulary version. Accepts OMOPHub version (2025.2) or FHIR ID (omop-v20250827) |
to | string | Yes | New vocabulary version. Same formats as from |
system | uri | No | Filter to a specific vocabulary |
count | integer | No | Max detail entries per category (default: 100, max: 1000) |
Response
{
"resourceType": "Parameters",
"parameter": [
{ "name": "from", "valueString": "2025.2" },
{ "name": "to", "valueString": "2026.1" },
{ "name": "total-added", "valueInteger": 1247 },
{ "name": "total-deprecated", "valueInteger": 83 },
{
"name": "added",
"part": [
{ "name": "code", "valueCode": "1234567" },
{ "name": "display", "valueString": "New concept name" },
{
"name": "property",
"part": [
{ "name": "code", "valueCode": "vocabulary-id" },
{ "name": "value", "valueCode": "SNOMED" }
]
}
]
},
{
"name": "deprecated",
"part": [
{ "name": "code", "valueCode": "7654321" },
{ "name": "display", "valueString": "Deprecated concept" },
{
"name": "property",
"part": [
{ "name": "code", "valueCode": "invalid-reason" },
{ "name": "value", "valueCode": "U" }
]
}
]
}
]
}
Errors
| HTTP | Issue Code | Cause |
|---|
| 400 | invalid | Missing from or to parameter, or unknown system URI |
| 404 | not-found | Version not found in vocabulary releases |
