Get Class Concepts

curl -X GET "https://api.omophub.com/v1/concept-classes/Clinical%20Finding/concepts?vocabulary_ids=SNOMED&page_size=20" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

{
  "success": true,
  "data": {
  "concept_class": {
    "concept_class_id": "Clinical Finding",
    "concept_class_name": "Clinical Finding",
    "concept_class_concept_id": 404684003,
    "description": "A clinical finding represents a result of an observation, assessment, or judgment"
  },
  "concepts": [
    {
      "concept_id": 201826,
      "concept_name": "Type 2 diabetes mellitus",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "44054006",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 4182210,
      "concept_name": "Hypertensive disorder",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "38341003",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 313217,
      "concept_name": "Atrial fibrillation",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "49436004",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    }
  ],
  "statistics": {
    "total_concepts_in_class": 156847,
    "filtered_concept_count": 98532,
    "standard_concept_count": 87124,
    "vocabulary_distribution": {
      "SNOMED": 87124,
      "ICD10CM": 7893,
      "ICD9CM": 3515
    },
    "domain_distribution": {
      "Condition": 92156,
      "Observation": 4891,
      "Measurement": 1485
    },
    "validity_status": {
      "valid": 96847,
      "invalid": 1685
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    },
    "request_id": "req_class_concepts_123456",
    "timestamp": "2024-12-22T10:30:00Z",
    "vocab_release": "2025.2"
  }
}

GET

https://api.omophub.com

concept-classes

{classId}

concepts

curl -X GET "https://api.omophub.com/v1/concept-classes/Clinical%20Finding/concepts?vocabulary_ids=SNOMED&page_size=20" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

{
  "success": true,
  "data": {
  "concept_class": {
    "concept_class_id": "Clinical Finding",
    "concept_class_name": "Clinical Finding",
    "concept_class_concept_id": 404684003,
    "description": "A clinical finding represents a result of an observation, assessment, or judgment"
  },
  "concepts": [
    {
      "concept_id": 201826,
      "concept_name": "Type 2 diabetes mellitus",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "44054006",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 4182210,
      "concept_name": "Hypertensive disorder",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "38341003",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 313217,
      "concept_name": "Atrial fibrillation",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "49436004",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    }
  ],
  "statistics": {
    "total_concepts_in_class": 156847,
    "filtered_concept_count": 98532,
    "standard_concept_count": 87124,
    "vocabulary_distribution": {
      "SNOMED": 87124,
      "ICD10CM": 7893,
      "ICD9CM": 3515
    },
    "domain_distribution": {
      "Condition": 92156,
      "Observation": 4891,
      "Measurement": 1485
    },
    "validity_status": {
      "valid": 96847,
      "invalid": 1685
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    },
    "request_id": "req_class_concepts_123456",
    "timestamp": "2024-12-22T10:30:00Z",
    "vocab_release": "2025.2"
  }
}

Overview

This endpoint returns all concepts that belong to a specific concept class, providing a way to explore concepts within a particular classification category. Concept classes group related concepts by their semantic type and purpose within medical terminology.

Path Parameters

classId

string

required

The concept class ID to retrieve concepts for (e.g., “Clinical Finding”, “Procedure”, “Substance”)

Query Parameters

vocabulary_ids

string

Comma-separated list of vocabulary IDs to filter concepts (e.g., “SNOMED,ICD10CM”)

domain_ids

string

Comma-separated list of domain IDs to filter concepts (e.g., “Condition,Drug”)

standard_concept

string

Filter by standard concept flag: “S” (standard), “C” (classification), or “N” (non-standard)

include_invalid

boolean

default:"false"

Include invalid/deprecated concepts in results

search_term

string

Filter concepts by name containing this search term

sort_by

string

default:"concept_name"

Sort results by: “concept_name”, “concept_id”, “concept_code”, or “vocabulary_id”

sort_order

string

default:"asc"

Sort order: “asc” or “desc”

vocab_release

string

Specific vocabulary release version (e.g., “2024.1”)

page

integer

default:"1"

Page number for pagination (1-based)

page_size

integer

default:"50"

Number of concepts per page

Response

concept_class

object

required

Information about the concept class

Show concept_class

concept_class_id

string

The concept class identifier

concept_class_name

string

Human-readable name of the concept class

concept_class_concept_id

integer

Concept ID representing this class

description

string

Description of the concept class

concepts

array

required

Array of concepts in this class

Show concepts

concept_id

integer

Unique OMOP concept identifier

concept_name

string

Human-readable concept name

vocabulary_id

string

Vocabulary that defines this concept

domain_id

string

Domain category of the concept

concept_class_id

string

The concept class (matches the requested classId)

standard_concept

string

Standard concept flag: “S”, “C”, “N”, or null

concept_code

string

Original code from the source vocabulary

valid_start_date

string

When this concept became valid (ISO date)

valid_end_date

string

When this concept expires (ISO date)

invalid_reason

string

Reason if concept is invalid (null if valid)

statistics

object

required

Statistics about concepts in this class

Show statistics

total_concepts_in_class

integer

Total number of concepts in this class (unfiltered)

filtered_concept_count

integer

Number of concepts matching current filters

standard_concept_count

integer

Number of standard concepts in results

vocabulary_distribution

object

Count of concepts by vocabulary

domain_distribution

object

Count of concepts by domain

validity_status

object

Count of concepts by validity status

curl -X GET "https://api.omophub.com/v1/concept-classes/Clinical%20Finding/concepts?vocabulary_ids=SNOMED&page_size=20" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

{
  "success": true,
  "data": {
  "concept_class": {
    "concept_class_id": "Clinical Finding",
    "concept_class_name": "Clinical Finding",
    "concept_class_concept_id": 404684003,
    "description": "A clinical finding represents a result of an observation, assessment, or judgment"
  },
  "concepts": [
    {
      "concept_id": 201826,
      "concept_name": "Type 2 diabetes mellitus",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "44054006",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 4182210,
      "concept_name": "Hypertensive disorder",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "38341003",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    },
    {
      "concept_id": 313217,
      "concept_name": "Atrial fibrillation",
      "vocabulary_id": "SNOMED",
      "domain_id": "Condition",
      "concept_class_id": "Clinical Finding",
      "standard_concept": "S",
      "concept_code": "49436004",
      "valid_start_date": "2002-01-31",
      "valid_end_date": "2099-12-31",
      "invalid_reason": null
    }
  ],
  "statistics": {
    "total_concepts_in_class": 156847,
    "filtered_concept_count": 98532,
    "standard_concept_count": 87124,
    "vocabulary_distribution": {
      "SNOMED": 87124,
      "ICD10CM": 7893,
      "ICD9CM": 3515
    },
    "domain_distribution": {
      "Condition": 92156,
      "Observation": 4891,
      "Measurement": 1485
    },
    "validity_status": {
      "valid": 96847,
      "invalid": 1685
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    }
  },
  "meta": {
    "pagination": {
      "page": 1,
      "page_size": 50,
      "total_items": 98532,
      "total_pages": 1971,
      "has_next": true,
      "has_previous": false
    },
    "request_id": "req_class_concepts_123456",
    "timestamp": "2024-12-22T10:30:00Z",
    "vocab_release": "2025.2"
  }
}

Usage Examples

Basic Class Exploration

Get all concepts in a specific class:

curl -X GET "https://api.omophub.com/v1/concept-classes/Procedure/concepts?page_size=100" \
  -H "Authorization: Bearer YOUR_API_KEY"

Standard Concepts Only

Get only standard concepts from SNOMED:

curl -X GET "https://api.omophub.com/v1/concept-classes/Clinical%20Finding/concepts?vocabulary_ids=SNOMED&standard_concept=S" \
  -H "Authorization: Bearer YOUR_API_KEY"

Search Within Class

Search for specific concepts within a class:

curl -X GET "https://api.omophub.com/v1/concept-classes/Substance/concepts?search_term=insulin&vocabulary_ids=RxNorm" \
  -H "Authorization: Bearer YOUR_API_KEY"

Cross-Vocabulary Analysis

Compare concepts across vocabularies:

curl -X GET "https://api.omophub.com/v1/concept-classes/Clinical%20Finding/concepts?vocabulary_ids=SNOMED,ICD10CM&domain_ids=Condition" \
  -H "Authorization: Bearer YOUR_API_KEY"

Taxonomy Building

Use for building classification hierarchies:

async function buildClassTaxonomy(classId, vocabularyIds = ['SNOMED']) {
  const response = await fetch(`/v1/concept-classes/${encodeURIComponent(classId)}/concepts?vocabulary_ids=${vocabularyIds.join(',')}&standard_concept=S&page_size=1000`);
  const data = await response.json();
  
  return {
    className: data.concept_class.concept_class_name,
    totalConcepts: data.statistics.total_concepts_in_class,
    standardConcepts: data.statistics.standard_concept_count,
    vocabularyBreakdown: data.statistics.vocabulary_distribution,
    sampleConcepts: data.concepts.slice(0, 10).map(c => ({
      id: c.concept_id,
      name: c.concept_name,
      code: c.concept_code,
      vocabulary: c.vocabulary_id
    }))
  };
}

Important Notes

URL encoding - Class IDs with spaces must be URL encoded (e.g., “Clinical Finding” → “Clinical%20Finding”)
Large result sets - Some concept classes contain hundreds of thousands of concepts; use pagination
Standard concepts - Filter by standard_concept=S for most clinical applications
Performance - Searching within large classes may take longer; consider using specific filters
Vocabulary coverage - Concept class availability varies by vocabulary

Get Concept Classes - List all available concept classes
Get Class Hierarchy - Hierarchical relationships between classes
Search Concepts - Free-text concept search with class filtering

Get Concept Classes Get Class Hierarchy

⌘I

API Reference

Concepts

Concept Hierarchy

Search

Search (Coming Soon)

Relationships

Domains & Classifications

Mappings

Vocabularies

Overview

Path Parameters

Query Parameters

Response

Usage Examples

Basic Class Exploration

Standard Concepts Only

Search Within Class

Cross-Vocabulary Analysis

Taxonomy Building

Important Notes

API Reference

Concepts

Concept Hierarchy

Search

Search (Coming Soon)

Relationships

Domains & Classifications

Mappings

Vocabularies

​Overview

​Path Parameters

​Query Parameters

​Response

​Usage Examples

​Basic Class Exploration

​Standard Concepts Only

​Search Within Class

​Cross-Vocabulary Analysis

​Taxonomy Building

​Important Notes

​Related Endpoints

Overview

Path Parameters

Query Parameters

Response

Usage Examples

Basic Class Exploration

Standard Concepts Only

Search Within Class

Cross-Vocabulary Analysis

Taxonomy Building

Important Notes

Related Endpoints