> ## Documentation Index
> Fetch the complete documentation index at: https://docs.omophub.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Get Vocabulary Domains

> Retrieve all OHDSI domains available within a specific OMOP vocabulary - filter by the domains SNOMED, ICD-10, or RxNorm actually cover.

Retrieve the list of standard OHDSI domains. Domains categorize concepts by their clinical or administrative function (e.g., Condition, Drug, Procedure).

## Query Parameters

<ParamField query="vocab_release" type="string">
  Specific vocabulary release version to use. If not provided, uses the latest available release.

  <br />

  **Format**: `YYYY.Q` (e.g., `2025.1`)
</ParamField>

## Response

<ResponseField name="success" type="boolean">
  Indicates if the request was successful.
</ResponseField>

<ResponseField name="data" type="object">
  <Expandable title="Data Object">
    <ResponseField name="domains" type="array">
      Array of domain objects.

      <Expandable title="Domain Object">
        <ResponseField name="domain_id" type="string">
          Unique domain identifier (e.g., "Condition", "Drug", "Procedure").
        </ResponseField>

        <ResponseField name="domain_name" type="string">
          Human-readable domain name.
        </ResponseField>

        <ResponseField name="description" type="string">
          Brief description of the domain.
        </ResponseField>
      </Expandable>
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="meta" type="object">
  <Expandable title="Metadata">
    <ResponseField name="request_id" type="string">
      Unique identifier for the request.
    </ResponseField>

    <ResponseField name="timestamp" type="string">
      Request timestamp.
    </ResponseField>

    <ResponseField name="vocab_release" type="string">
      Vocabulary release version used.
    </ResponseField>
  </Expandable>
</ResponseField>

<RequestExample>
  ```bash cURL theme={null}
  curl -X GET "https://api.omophub.com/v1/vocabularies/domains" \
    -H "Authorization: Bearer YOUR_API_KEY"
  ```

  ```python Python theme={null}
  import requests

  response = requests.get(
      "https://api.omophub.com/v1/vocabularies/domains",
      headers={"Authorization": "Bearer YOUR_API_KEY"}
  )
  data = response.json()
  for domain in data["data"]["domains"]:
      print(f"{domain['domain_id']}: {domain['domain_name']}")
  ```

  ```javascript JavaScript theme={null}
  const response = await fetch('https://api.omophub.com/v1/vocabularies/domains', {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  });
  const data = await response.json();
  console.log(data.data.domains);
  ```
</RequestExample>

<ResponseExample>
  ```json Response theme={null}
  {
    "success": true,
    "data": {
      "domains": [
        {
          "domain_id": "Condition",
          "domain_name": "Condition",
          "description": "OHDSI standard domain: Condition"
        },
        {
          "domain_id": "Drug",
          "domain_name": "Drug",
          "description": "OHDSI standard domain: Drug"
        },
        {
          "domain_id": "Procedure",
          "domain_name": "Procedure",
          "description": "OHDSI standard domain: Procedure"
        },
        {
          "domain_id": "Measurement",
          "domain_name": "Measurement",
          "description": "OHDSI standard domain: Measurement"
        },
        {
          "domain_id": "Observation",
          "domain_name": "Observation",
          "description": "OHDSI standard domain: Observation"
        },
        {
          "domain_id": "Device",
          "domain_name": "Device",
          "description": "OHDSI standard domain: Device"
        },
        {
          "domain_id": "Specimen",
          "domain_name": "Specimen",
          "description": "OHDSI standard domain: Specimen"
        },
        {
          "domain_id": "Visit",
          "domain_name": "Visit",
          "description": "OHDSI standard domain: Visit"
        }
      ]
    },
    "meta": {
      "request_id": "req_abc123def456",
      "timestamp": "2025-01-05T10:30:00Z",
      "vocab_release": "2025.1"
    }
  }
  ```
</ResponseExample>

## Available Domains

The endpoint returns all standard OHDSI domains:

### Clinical Domains

* **Condition** - Diseases, disorders, and clinical findings
* **Procedure** - Medical procedures and interventions
* **Observation** - Clinical observations and assessments
* **Measurement** - Quantitative test results and vital signs
* **Drug** - Medications and pharmaceutical products
* **Device** - Medical devices and equipment
* **Specimen** - Biological specimens and samples

### Administrative Domains

* **Visit** - Healthcare encounters and visit types
* **Provider** - Healthcare provider roles and specialties
* **Location** - Geographic locations
* **Care Site** - Healthcare facilities
* **Payer** - Insurance and payment-related concepts
* **Plan** - Insurance plans
* **Sponsor** - Study sponsors
* **Cost** - Healthcare cost information
* **Revenue** - Revenue codes

### Other Domains

* **Episode** - Clinical episodes
* **Regimen** - Treatment regimens
* **Metadata** - Vocabulary metadata
* **Type Concept** - Type concepts
* **Relationship** - Relationship types
* **Gender** - Gender concepts
* **Race** - Race concepts
* **Ethnicity** - Ethnicity concepts

## Related Endpoints

* [Get Domains](/api-reference/domains/get-domains) - Detailed domain information with statistics
* [Get Domain Concepts](/api-reference/domains/get-domain-concepts) - Concepts within a specific domain
* [List Vocabularies](/api-reference/vocabularies/list-vocabularies) - Available vocabularies