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

integer

required

The unique concept identifier

Query Parameters

string

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

string

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

string

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

boolean

default:"true"

Include relationships to invalid concepts

boolean

default:"false"

Only include relationships to standard concepts

boolean

default:"false"

Include reverse relationships (where this concept is the target)

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

boolean

Indicates if the request was successful

object

Show Response Data

array

Array of relationship objects

Show Relationship

string

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

integer

Source concept ID

integer

Target concept ID

string

Target concept name

string

Target concept code

string

Target vocabulary ID

string

Target domain ID

string

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

string

Relationship validity start date

string

Relationship validity end date

object

Show Metadata

string

Unique identifier for the request

string

Request timestamp (ISO 8601 UTC format)

string

Vocabulary release version used

string

Schema version used for the query

integer

Request duration in milliseconds

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