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curl -X GET "https://api.omophub.com/v1/domains?include_stats=true" \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "success": true,
  "data": {
    "domains": [
      {
        "domain_id": "Condition",
        "domain_name": "Condition",
        "domain_concept_id": 19
      },
      {
        "domain_id": "Drug",
        "domain_name": "Drug",
        "domain_concept_id": 13
      },
      {
        "domain_id": "Procedure",
        "domain_name": "Procedure",
        "domain_concept_id": 10
      },
      {
        "domain_id": "Measurement",
        "domain_name": "Measurement",
        "domain_concept_id": 21
      },
      {
        "domain_id": "Observation",
        "domain_name": "Observation",
        "domain_concept_id": 27
      }
    ]
  },
  "meta": {
    "request_id": "req_abc123",
    "vocab_release": "2025.1"
  }
}
This endpoint provides information about all domains available in the OMOP vocabulary system. Domains represent high-level categorizations that group medical concepts by their semantic meaning, such as Condition, Drug, Procedure, and others.

​
Query Parameters

​
include_stats
boolean
default:"false"
Include concept counts and vocabulary coverage for each domain
​
vocab_release
string
Specific vocabulary release version to query
Example: 2025.1

​
Response

​
domains
array
Array of domain objects with their properties
​
meta
object
Response metadata
curl -X GET "https://api.omophub.com/v1/domains?include_stats=true" \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "success": true,
  "data": {
    "domains": [
      {
        "domain_id": "Condition",
        "domain_name": "Condition",
        "domain_concept_id": 19
      },
      {
        "domain_id": "Drug",
        "domain_name": "Drug",
        "domain_concept_id": 13
      },
      {
        "domain_id": "Procedure",
        "domain_name": "Procedure",
        "domain_concept_id": 10
      },
      {
        "domain_id": "Measurement",
        "domain_name": "Measurement",
        "domain_concept_id": 21
      },
      {
        "domain_id": "Observation",
        "domain_name": "Observation",
        "domain_concept_id": 27
      }
    ]
  },
  "meta": {
    "request_id": "req_abc123",
    "vocab_release": "2025.1"
  }
}

​
Usage Examples

​
Basic Domain List

Get all available domains:
TypeScript
const { data } = await client.domains.list();
console.log(data?.domains);

​
Domains with Statistics

Get domains with concept counts and vocabulary coverage:
TypeScript
const { data } = await client.domains.list({ includeStats: true });

// Find the domain with the most concepts
const largestDomain = data?.domains.reduce<{ domain_name?: string; concept_count?: number }>(
  (max, domain) => ((domain.concept_count ?? 0) > (max.concept_count ?? 0) ? domain : max),
  {},
);

console.log(`Largest domain: ${largestDomain?.domain_name} with ${largestDomain?.concept_count} concepts`);

​
Filter by Vocabulary Coverage

Find domains that include concepts from a specific vocabulary:
TypeScript
const { data } = await client.domains.list({ includeStats: true });

// Find domains with SNOMED concepts
const snomedDomains = data?.domains.filter(domain =>
  domain.vocabulary_coverage?.includes('SNOMED'),
);

console.log('Domains with SNOMED concepts:', snomedDomains?.map(d => d.domain_name));

​
Notes

  • Domains provide the highest level of semantic categorization in OMOP
  • The most commonly used clinical domains are Condition, Drug, Procedure, and Measurement
  • Use include_stats=true to get concept counts for capacity planning and analysis
  • The vocabulary_coverage field shows which vocabularies contribute concepts to each domain