Get Concept Relationships

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"}
)
relationships = response.json()

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
// `data` is `{ relationships: ConceptRelationship[] }` — the array is at
// `data.relationships`, not `data` itself.
const { data } = await client.concepts.relationships(320128);
console.log(`Found ${data?.relationships.length ?? 0} relationships`);

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?relationship_ids=Is%20a&vocabulary_ids=SNOMED" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

params = {
    "relationship_ids": "Is a",
    "vocabulary_ids": "SNOMED",
    "standard_only": True
}
response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    params=params
)
filtered_relationships = response.json()

{
  "success": true,
  "data": {
    "relationships": [
      {
        "relationship_id": "Is a",
        "concept_id_1": 320128,
        "concept_id_2": 316866,
        "concept_name": "Hypertensive disorder",
        "concept_code": "38341003",
        "vocabulary_id": "SNOMED",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Maps to",
        "concept_id_1": 320128,
        "concept_id_2": 435216,
        "concept_name": "Essential hypertension",
        "concept_code": "I10",
        "vocabulary_id": "ICD10CM",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Has finding site",
        "concept_id_1": 320128,
        "concept_id_2": 4103720,
        "concept_name": "Cardiovascular system",
        "concept_code": "113257007",
        "vocabulary_id": "SNOMED",
        "domain_id": "Spec Anatomic Site",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      }
    ]
  },
  "meta": {
    "request_id": "req_relationships_123",
    "timestamp": "2024-12-22T10:00:00Z",
    "vocab_release": "2025.2",
    "version": "2025.2",
    "duration": 45
  }
}

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"}
)
relationships = response.json()

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
// `data` is `{ relationships: ConceptRelationship[] }` — the array is at
// `data.relationships`, not `data` itself.
const { data } = await client.concepts.relationships(320128);
console.log(`Found ${data?.relationships.length ?? 0} relationships`);

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?relationship_ids=Is%20a&vocabulary_ids=SNOMED" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

params = {
    "relationship_ids": "Is a",
    "vocabulary_ids": "SNOMED",
    "standard_only": True
}
response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    params=params
)
filtered_relationships = response.json()

{
  "success": true,
  "data": {
    "relationships": [
      {
        "relationship_id": "Is a",
        "concept_id_1": 320128,
        "concept_id_2": 316866,
        "concept_name": "Hypertensive disorder",
        "concept_code": "38341003",
        "vocabulary_id": "SNOMED",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Maps to",
        "concept_id_1": 320128,
        "concept_id_2": 435216,
        "concept_name": "Essential hypertension",
        "concept_code": "I10",
        "vocabulary_id": "ICD10CM",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Has finding site",
        "concept_id_1": 320128,
        "concept_id_2": 4103720,
        "concept_name": "Cardiovascular system",
        "concept_code": "113257007",
        "vocabulary_id": "SNOMED",
        "domain_id": "Spec Anatomic Site",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      }
    ]
  },
  "meta": {
    "request_id": "req_relationships_123",
    "timestamp": "2024-12-22T10:00:00Z",
    "vocab_release": "2025.2",
    "version": "2025.2",
    "duration": 45
  }
}

Overview

Retrieve all relationships for a concept, including hierarchical relationships (parents/children), mappings to other vocabularies, and semantic relationships.

Path Parameters

conceptId

integer

required

The unique concept identifier

Query Parameters

relationship_ids

string

Filter by relationship type IDs (comma-separated)
Examples: Is a, Subsumes, Maps to, Is a,Subsumes

vocabulary_ids

string

Filter relationships to specific target vocabularies (comma-separated)
Examples: SNOMED, ICD10CM, SNOMED,ICD10CM

domain_ids

string

Filter relationships to specific target domains (comma-separated)
Examples: Condition, Drug, Condition,Procedure

include_invalid

boolean

default:"true"

Include relationships to invalid concepts

standard_only

boolean

default:"false"

Only include relationships to standard concepts

include_reverse

boolean

default:"false"

Include reverse relationships (where this concept is the target)

vocab_release

string

Specific vocabulary release version (defaults to latest)

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"}
)
relationships = response.json()

import { OMOPHub } from '@omophub/omophub-node';

const client = new OMOPHub();
// `data` is `{ relationships: ConceptRelationship[] }` — the array is at
// `data.relationships`, not `data` itself.
const { data } = await client.concepts.relationships(320128);
console.log(`Found ${data?.relationships.length ?? 0} relationships`);

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?relationship_ids=Is%20a&vocabulary_ids=SNOMED" \
  -H "Authorization: Bearer YOUR_API_KEY"

import requests

params = {
    "relationship_ids": "Is a",
    "vocabulary_ids": "SNOMED",
    "standard_only": True
}
response = requests.get(
    "https://api.omophub.com/v1/concepts/320128/relationships",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    params=params
)
filtered_relationships = response.json()

{
  "success": true,
  "data": {
    "relationships": [
      {
        "relationship_id": "Is a",
        "concept_id_1": 320128,
        "concept_id_2": 316866,
        "concept_name": "Hypertensive disorder",
        "concept_code": "38341003",
        "vocabulary_id": "SNOMED",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Maps to",
        "concept_id_1": 320128,
        "concept_id_2": 435216,
        "concept_name": "Essential hypertension",
        "concept_code": "I10",
        "vocabulary_id": "ICD10CM",
        "domain_id": "Condition",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      },
      {
        "relationship_id": "Has finding site",
        "concept_id_1": 320128,
        "concept_id_2": 4103720,
        "concept_name": "Cardiovascular system",
        "concept_code": "113257007",
        "vocabulary_id": "SNOMED",
        "domain_id": "Spec Anatomic Site",
        "standard_concept": "S",
        "valid_start_date": "1970-01-01",
        "valid_end_date": "2099-12-31"
      }
    ]
  },
  "meta": {
    "request_id": "req_relationships_123",
    "timestamp": "2024-12-22T10:00:00Z",
    "vocab_release": "2025.2",
    "version": "2025.2",
    "duration": 45
  }
}

Response Fields

success

boolean

Indicates if the request was successful

data

object

Show Response Data

relationships

array

Array of relationship objects

Show Relationship

relationship_id

string

Type of relationship (e.g., “Is a”, “Maps to”, “Subsumes”)

concept_id_1

integer

Source concept ID

concept_id_2

integer

Target concept ID

concept_name

string

Target concept name

concept_code

string

Target concept code

vocabulary_id

string

Target vocabulary ID

domain_id

string

Target domain ID

standard_concept

string

Standard concept flag (S=Standard, C=Classification, null=Non-standard)

valid_start_date

string

Relationship validity start date

valid_end_date

string

Relationship validity end date

Usage Examples

Get All Relationships

Retrieve all relationships for a concept:

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships" \
  -H "Authorization: Bearer YOUR_API_KEY"

Filter by Relationship Type

Get only hierarchical relationships:

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?relationship_ids=Is%20a,Subsumes" \
  -H "Authorization: Bearer YOUR_API_KEY"

Filter by Target Vocabulary

Get mappings to specific vocabularies:

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?vocabulary_ids=ICD10CM,ICD9CM" \
  -H "Authorization: Bearer YOUR_API_KEY"

Standard Concepts Only

Get relationships to standard concepts only:

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?standard_only=true" \
  -H "Authorization: Bearer YOUR_API_KEY"

Include Reverse Relationships

Include relationships where this concept is the target:

curl -X GET "https://api.omophub.com/v1/concepts/320128/relationships?include_reverse=true" \
  -H "Authorization: Bearer YOUR_API_KEY"

Common Relationship Types

Relationship	Description
`Is a`	Hierarchical parent relationship
`Subsumes`	Hierarchical child relationship
`Maps to`	Mapping to another vocabulary
`Mapped from`	Reverse mapping relationship
`Has finding site`	Anatomical location
`Has associated morphology`	Associated morphological finding

Get Concept - Get detailed concept information
Get Relationship Options - Get available relationship types for a concept
Traverse Relationships - Complex relationship traversal

API Reference

Search

Concepts

Concept Hierarchy

Mappings

FHIR Resolver

Relationships

Domains & Classifications

Vocabularies

Overview

Path Parameters

Query Parameters

Response Fields

Usage Examples

Get All Relationships

Filter by Relationship Type

Filter by Target Vocabulary

Standard Concepts Only

Include Reverse Relationships

Common Relationship Types

​Overview

​Path Parameters

​Query Parameters

​Response Fields

​Usage Examples

​Get All Relationships

​Filter by Relationship Type

​Filter by Target Vocabulary

​Standard Concepts Only

​Include Reverse Relationships

​Common Relationship Types

​Related Endpoints

Overview

Path Parameters

Query Parameters

Response Fields

Usage Examples

Get All Relationships

Filter by Relationship Type

Filter by Target Vocabulary

Standard Concepts Only

Include Reverse Relationships

Common Relationship Types

Related Endpoints