First-Class Extensions Using Attribute

Since the 2405 release, using Aidbox in FHIRSchema mode is recommended, which is incompatible with zen or Entity/Attribute options.

Setup Aidbox with FHIR Schema validation engine

In Aidbox there are two ways to define first-class extensions:

Using Zen profiles
Using Attribute

If you're using Aidbox with zen, all resources will be validated by zen, not Attributes. In this case, you should use zen profiles.

If you don't use zen, you can use Attributes.

Define new extension with Attribute

In Aidbox, you can define first-class extensions using the custom resource Attribute.

Let's create an extension definition of type Reference in the REST Console of Aidbox:

Create new extension in the Aidbox format:

PUT /Attribute/ServiceRequest.requestedOrganizationDepartment

description: Department in the organization that made the service request
resource: {id: ServiceRequest, resourceType: Entity}
path: [requestedOrganizationDepartment]
type: {id: Reference, resourceType: Entity}
refers: 
  - Organization
extensionUrl: urn:extension:requestedOrganizationDepartment

description - string.

Attribute text description
resource - required, Reference(Entity).

Reference to a target resource type
path - required, an array of strings.

Path to a new attribute location in the target resource type
type - Reference(Entity).

Type of data stored in this attribute. It can be any primitive or complex type.

If omitted, treated asBackboneElement, i.e. a complex-type object with structure defined via other Attributes relying on this attribute in their path
isCollection - boolean.

Whether the attribute is a collection, i.e. if true sets attribute cardinality to ..*
isRequired - boolean.

Whether the attribute is required, i.e. if true sets attribute cardinality to 1..
isUnique - boolean.
Sets unique restriction on the attribute.
refers - Reference(Entity).

Only for type=Reference. Specifies to which resourceTypes this reference can refer to
extensionUrl - string.

URL which will be used to create extension element in FHIR format. If omitted, the Attribute won't be transformed into the FHIR format

Note: you can not use Attributes and zen profiles on the same resource at the same time

Use your extension

Now, you can create the ServiceRequest resource using the new attribute requestedOrganizationDepartment in the root of the resource:

Create resource in the Aidbox format:

PUT /ServiceRequest/servicerequest-with-aidbox-native-extensions

requestedOrganizationDepartment:
  resourceType: Organization
  display: City Hospital Neurology Department
  identifier: {system: 'urn:oid:1.2.3.4.5.6.7.8', value: '456'}
category:
- coding:
  - {code: '183829003', 
    system: 'http://snomed.info/sct', 
    display: "Refer for imaging"}
authoredOn: '2020-01-18T15:08:00'
resourceType: ServiceRequest
requester:
  resourceType: PractitionerRole
  display: Din Morgan
  identifier: {value: "1760", system: 'urn:oid:1.2.3.4.5.6.7.6'}
priority: routine
status: active
intent: original-order
performer:
- resourceType: Organization
  display: Aga Khan University Hospital Laboratory
  identifier: {value: "1514", system: 'urn:oid:1.2.3.4.5.6.7.8'}
subject:
  resourceType: Patient
  display: Jack Black, 10.12.1941
  identifier: {value: '2155800871000065', system: 'urn:oid:1.2.3.4.5.6.7.9'}

FHIR Format

You can get the resource in the FHIR format where our new attribute is rendered as the extension element:

Note that the URL is different:GET /fhir/ServiceRequest/

Get the resource in the FHIR format:

GET /fhir/ServiceRequest/servicerequest-with-aidbox-native-extensions

extension:
- url: urn:extension:requestedOrganizationDepartment
  valueReference:
    type: Organization
    identifier: {value: '456', system: 'urn:oid:1.2.3.4.5.6.7.8'}
    display: City Hospital Neurology Department
category:
- coding:
  - {code: '183829003', 
    system: 'http://snomed.info/sct', 
    display: "Refer for imaging"}
meta:
  lastUpdated: '2020-02-04T09:15:18.664293Z'
  versionId: '32'
  extension:
  - {url: 'ex:createdAt', valueInstant: '2020-02-04T09:12:20.103301Z'}
authoredOn: '2020-01-18T15:08:00'
resourceType: ServiceRequest
requester:
  type: PractitionerRole
  identifier: {value: '1760', system: 'urn:oid:1.2.3.4.5.6.7.6'}
  display: Din Morgan
priority: routine
status: active
id: servicerequest-with-aidbox-native-extensions
intent: original-order
subject:
  type: Patient
  identifier: {value: '2155800871000065', 
              system: 'urn:oid:1.2.3.4.5.6.7.9'}
  display: Jack Black, 10.12.1941
performer:
- type: Organization
  identifier: {value: '1514', system: 'urn:oid:1.2.3.4.5.6.7.8'}
  display: Aga Khan University Hospital Laboratory

Other extension examples

Let's create an extension of type Reference and list allowed resource types (Organization in that case) in the refers property.

managingOrganization

PUT /Attribute/ServiceRequest.managingOrganization

resourceType: Attribute
description: Organization that made the service request
resource: {id: ServiceRequest, resourceType: Entity}
path: [managingOrganization]
id: ServiceRequest.managingOrganization
type: {id: Reference, resourceType: Entity}
refers: 
  - Organization
extensionUrl: urn:extension:requestedOrganization

Extension of type Coding:

paymentType

PUT /Attribute/ServiceRequest.paymentType

resourceType: Attribute
description: Payment type for the service request, e.g. government health insurance
id: ServiceRequest.paymentType
resource:
  id: ServiceRequest
  resourceType: Entity
path:
- paymentType
type:
  id: Coding
  resourceType: Entity
extensionUrl: urn:extension:paymentType

Create resource using these extensions:

PUT /ServiceRequest/servicerequest-with-aidbox-native-extensions

managingOrganization:
  resourceType: Organization
  display: City Hospital
  identifier: {value: "123", system: 'urn:oid:1.2.3.4.5.6.7.8'}
requestedOrganizationDepartment:
  resourceType: Organization
  display: City Hospital Neurology Department
  identifier: {system: 'urn:oid:1.2.3.4.5.6.7.8', value: '456'}
paymentType: {system: 'urn:CodeSystem:paymentType', 
              code: "1", 
              display: "Government Health Insurance"}
resourceType: ServiceRequest
status: active
intent: original-order
subject:
  resourceType: Patient
  display: Jack Black, 10.12.1941
  identifier: {value: '2155800871000065', system: 'urn:oid:1.2.3.4.5.6.7.9'}

Get resource in the FHIR format:

GET /fhir/ServiceRequest/servicerequest-with-aidbox-native-extensions

resourceType: ServiceRequest
extension:
- url: urn:extension:requestedOrganization
  valueReference:
    type: Organization
    identifier: {value: '123', system: 'urn:oid:1.2.3.4.5.6.7.8'}
    display: City Hospital
- url: urn:extension:requestedOrganizationDepartment
  valueReference:
    type: Organization
    identifier: {value: '456', system: 'urn:oid:1.2.3.4.5.6.7.8'}
    display: City Hospital Neurology Department
- url: urn:extension:paymentType
  valueCoding: {code: '1', 
                system: 'urn:CodeSystem:paymentType', 
                display: Government Health Insurance}
status: active
id: servicerequest-with-aidbox-native-extensions
intent: original-order
subject:
  type: Patient
  identifier: {value: '2155800871000065', system: 'urn:oid:1.2.3.4.5.6.7.9'}
  display: Jack Black, 10.12.1941

Nested extensions

Let's create a structure of nested attributes:

performerInfo

PUT /Attribute/ServiceRequest.performerInfo

resourceType: Attribute
description: Information filled in by performer
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo]
id: ServiceRequest.performerInfo
extensionUrl: urn:extension:performerInfo

performerInfo.performedBy

PUT /Attribute/ServiceRequest.performerInfo.performedBy

resourceType: Attribute
description: 'Information filled in by performer: performed by ["Practitioner" "PractitionerRole" "Organization" "CareTeam" "HealthcareService" "Patient" "Device" "RelatedPerson"]'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, performedBy]
id: ServiceRequest.performerInfo.performedBy
type: {id: Reference, resourceType: Entity}
isCollection: true
refers: 
  - Practitioner
  - PractitionerRole
  - Organization
  - CareTeam
  - HealthcareService
  - Patient
  - Device
  - RelatedPerson
extensionUrl: urn:extension:performerInfo.performedBy

performerInfo.actualLocationReference

PUT /Attribute/ServiceRequest.performerInfo.actualLocationReference

resourceType: Attribute
description: 'Information filled in by performer: actual location reference'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, actualLocationReference]
id: ServiceRequest.performerInfo.actualLocationReference
type: {id: Reference, resourceType: Entity}
isCollection: true
refers: 
  - Location
extensionUrl: urn:extension:performerInfo.actualLocationReference

performerInfo.requestStatus

PUT /Attribute/ServiceRequest.performerInfo.requestStatus

resourceType: Attribute
description: 'Information filled in by performer: request status'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestStatus]
id: ServiceRequest.performerInfo.requestStatus
type: {id: code, resourceType: Entity}
enum:
  - draft
  - new
  - in-progress
  - suspended
  - expanded
  - completed
  - archive
  - cancelled
extensionUrl: urn:extension:performerInfo.requestStatus

performerInfo.requestActionHistory

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory

resourceType: Attribute
description: 'Information filled in by performer: request action history'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory]
id: ServiceRequest.performerInfo.requestActionHistory
isCollection: true
extensionUrl: urn:extension:performerInfo.requestActionHistory

performerInfo.requestActionHistory.action

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory.action

resourceType: Attribute
description: 'Information filled in by performer: request action history - action'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory, action]
id: ServiceRequest.performerInfo.requestActionHistory.action
type: {id: string, resourceType: Entity}
extensionUrl: urn:extension:performerInfo.requestActionHistory.action

performerInfo.requestActionHistory.date

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory.date

resourceType: Attribute
description: 'Information filled in by performer: request action history - date'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory, date]
id: ServiceRequest.performerInfo.requestActionHistory.date
type: {id: dateTime, resourceType: Entity}
extensionUrl: urn:extension:performerInfo.requestActionHistory.date

performerInfo.requestActionHistory.subject

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory.subject

resourceType: Attribute
description: 'Information filled in by performer: request action history - subject'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory, subject]
id: ServiceRequest.performerInfo.requestActionHistory.subject
type: {id: Reference, resourceType: Entity}
extensionUrl: urn:extension:performerInfo.requestActionHistory.subject

performerInfo.requestActionHistory.note

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory.note

resourceType: Attribute
description: 'Information filled in by performer: request action history - note'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory, note]
id: ServiceRequest.performerInfo.requestActionHistory.note
type: {id: string, resourceType: Entity}
extensionUrl: urn:extension:performerInfo.requestActionHistory.note

performerInfo.requestActionHistory.author

PUT /Attribute/ServiceRequest.performerInfo.requestActionHistory.author

resourceType: Attribute
description: 'Information filled in by performer: request action history - author'
resource: {id: ServiceRequest, resourceType: Entity}
path: [performerInfo, requestActionHistory, author]
id: ServiceRequest.performerInfo.requestActionHistory.author
type: {id: Reference, resourceType: Entity}
extensionUrl: urn:extension:performerInfo.requestActionHistory.author

Let's add a resource using created extensions:

Create resource in the Aidbox format:

PUT /ServiceRequest/servicerequest-with-aidbox-native-extensions

resourceType: ServiceRequest
performerInfo:
  performedBy:
  - resourceType: Organization
    display: City Hospital
  - resourceType: PractitionerRole
    display: Mark Sloan
  requestStatus: completed
  requestActionHistory:
  - date: '2020-01-14T12:15:22'
    action: new
    author: {display: Meredith Grey (Psychiatrist-narcologist), resourceType: PractitionerRole}
  - date: '2020-01-14T12:15:36'
    action: in-progress
    author: {display: Derek Shepherd (General practitioner), resourceType: PractitionerRole}
  - date: '2020-01-14T12:19:00'
    action: in-progress
    author: {display: Derek Shepherd (General practitioner), resourceType: PractitionerRole}
    subject: {display: Mark Sloan (Dental surgeon), resourceType: PractitionerRole}
    note: Referred to Dr. Mark Sloan (Dental surgeon)
  - date: '2020-01-14T15:05:20'
    action: meeting
    author: {display: Mark Sloan (Dental surgeon), resourceType: PractitionerRole}
  - date: '2020-01-14T15:22:46'
    action: completed
    author: {display: Mark Sloan (Dental surgeon), resourceType: PractitionerRole}    
status: completed
intent: original-order
category:
- text: Telemedicine consultation referral
  coding:
  - {code: "TMC", system: 'urn:CodeSystem:servicerequest-category', display: "Telemedicine consultation"}
subject:
  resourceType: Patient
  display: Jack Black, 10.12.1941
  identifier: {value: '2155800871000065', system: 'urn:oid:1.2.3.4.5.6.7.9'}

Get resource in the FHIR format:

GET /fhir/ServiceRequest/servicerequest-with-aidbox-native-extensions

resourceType: ServiceRequest
extension:
- url: urn:extension:performerInfo
  extension:
  - url: urn:extension:performerInfo.performedBy
    valueReference: {display: City Hospital}
  - url: urn:extension:performerInfo.performedBy
    valueReference: {display: Mark Sloan}
  - {url: 'urn:extension:performerInfo.requestStatus', valueCode: completed}
  - url: urn:extension:performerInfo.requestActionHistory
    extension:
    - {url: 'urn:extension:performerInfo.requestActionHistory.date', valueDateTime: '2020-01-14T12:15:22'}
    - {url: 'urn:extension:performerInfo.requestActionHistory.action', valueString: new}
    - url: urn:extension:performerInfo.requestActionHistory.author
      valueReference: {display: Meredith Grey (Psychiatrist-narcologist)}
  - url: urn:extension:performerInfo.requestActionHistory
    extension:
    - {url: 'urn:extension:performerInfo.requestActionHistory.date', valueDateTime: '2020-01-14T12:15:36'}
    - {url: 'urn:extension:performerInfo.requestActionHistory.action', valueString: in-progress}
    - url: urn:extension:performerInfo.requestActionHistory.author
      valueReference: {display: Derek Shepherd (General practitioner)}
  - url: urn:extension:performerInfo.requestActionHistory
    extension:
    - {url: 'urn:extension:performerInfo.requestActionHistory.date', valueDateTime: '2020-01-14T12:19:00'}
    - {url: 'urn:extension:performerInfo.requestActionHistory.note', valueString: Referred to Dr. Mark Sloan (Dental surgeon)}
    - {url: 'urn:extension:performerInfo.requestActionHistory.action', valueString: in-progress}
    - url: urn:extension:performerInfo.requestActionHistory.author
      valueReference: {display: Derek Shepherd (General practitioner)}
    - url: urn:extension:performerInfo.requestActionHistory.subject
      valueReference: {display: Mark Sloan (Dental surgeon)}
  - url: urn:extension:performerInfo.requestActionHistory
    extension:
    - {url: 'urn:extension:performerInfo.requestActionHistory.date', valueDateTime: '2020-01-14T15:05:20'}
    - {url: 'urn:extension:performerInfo.requestActionHistory.action', valueString: meeting}
    - url: urn:extension:performerInfo.requestActionHistory.author
      valueReference: {display: Mark Sloan (Dental surgeon)}
    - url: urn:extension:performerInfo.requestActionHistory.subject
      valueReference: {display: '2020-01-08'}
  - url: urn:extension:performerInfo.requestActionHistory
    extension:
    - {url: 'urn:extension:performerInfo.requestActionHistory.date', valueDateTime: '2020-01-14T15:22:46'}
    - {url: 'urn:extension:performerInfo.requestActionHistory.action', valueString: completed}
    - url: urn:extension:performerInfo.requestActionHistory.author
      valueReference: {display: Mark Sloan (Dental surgeon)}
status: completed
id: servicerequest-with-aidbox-native-extensions
intent: original-order
category:
- text: Telemedicine consultation referral
  coding:
  - {code: TMC, system: 'urn:CodeSystem:servicerequest-category', display: Telemedicine consultation}
subject:
  identifier: {value: '2155800871000065', system: 'urn:oid:1.2.3.4.5.6.7.9'}
  display: Jack Black, 10.12.1941

Using FHIR extensions

Let's create an attribute for the servicerequest-precondition extension:

PUT /Attribute/ServiceRequest.precondition

resourceType: Attribute
description: "The condition or state of the patient, prior or during 
the diagnostic procedure or test, for example, fasting, at-rest, 
or post-operative. This captures circumstances that may influence 
the measured value and have bearing on the interpretation of the result."
resource: {id: ServiceRequest, resourceType: Entity}
path: [precondition]
id: ServiceRequest.precondition
type: {id: CodeableConcept, resourceType: Entity}
isCollection: true
extensionUrl: "http://hl7.org/fhir/StructureDefinition/servicerequest-precondition"

Let's create a resource in the FHIR format:

Create resource in the FHIR format:

PUT /fhir/ServiceRequest/servicerequest-with-aidbox-native-extensions

resourceType: ServiceRequest
status: active
intent: original-order
subject:
  type: Patient
  display: Jack Black, 10.12.1941
extension:
  - url: http://hl7.org/fhir/StructureDefinition/servicerequest-precondition
    valueCodeableConcept:
      text: After calorie fasting
      coding:
        - code: "726055006"
          system: http://snomed.info/sct
          display: After calorie fasting
  - url: http://hl7.org/fhir/StructureDefinition/servicerequest-precondition
    valueCodeableConcept:
      text: At rest
      coding:
        - code: "263678003"
          system: http://snomed.info/sct
          display: At rest

Let's get the resource in the Aidbox format:

Get resource in the Aidbox format:

GET /ServiceRequest/servicerequest-with-aidbox-native-extensions

resourceType: ServiceRequest
id: servicerequest-with-aidbox-native-extensions
intent: original-order
status: active
subject: {type: Patient, display: 'Jack Black, 10.12.1941'}
precondition:
- text: After calorie fasting
  coding:
  - {code: '726055006', 
    system: 'http://snomed.info/sct', 
    display: After calorie fasting}
- text: At rest
  coding:
  - {code: '263678003', 
    system: 'http://snomed.info/sct', 
    display: At rest}

Create FHIR primitive type extension

FHIR primitive named fieldName can be extended with _fieldName field. Aidbox treats fieldName as independent from fieldName. Aidbox do not validate fields with names started with underscore.

Suppose we need to extend Patient.gender attribute with primitive type. It means, that we need to create Patient._gender attribute.

PUT /Attribute/Patient._gender

path:
  - _gender
resource:
  id: Patient
  resourceType: Entity
id: Patient._gender
resourceType: Attribute

Now we can add an extension attribute into _gender attribute.

PUT /Attribute/Patient._gender.extension

path:
  - _gender
  - extension
resource:
  id: Patient
  resourceType: Entity
id: Patient._gender.extension
isCollection: true
type:
  id: Extension
  resourceType: Entity
resourceType: Attribute

Finally, add Patient with extended gender.

PUT /Patient/p-gender

gender: male
_gender: 
  extension:
    - valueCodeableConcept: 
        coding:
          - code: code-male
            system: system-gender
      url: https://example.com