Others titles

  • FHIR Activity Definition Resource
  • Electronic Health Records Exchange Through FHIR


  • FHIR
  • HL7
  • Medical Terminology
  • Processes Data
  • Processes Information
  • Processes Documentation
  • Health Information Exchange
  • Electronic Health Records
  • FHIR Smart
  • Smart on FHIR

Activity Definition

An Activity Definition is a shareable, consumable description of some activity to be performed. It may be used to specify actions to be taken as part of a workflow, order set, or protocol, or it may be used independently as part of a catalog of activities such as orderables.

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In general, an activity definition is simply a conceptual description of some specific action that should be taken. An instance of an Activity Definition does not indicate that any action has been performed (as an event resource does), nor does it indicate the actual intent to carry out any particular action (as a request resource does). Instead, an activity definition provides a reusable template that can be used to construct specific request resources such as Service Request and Medication Request.

Note that this is conceptually similar to the Task resource as well, with the distinction being that Activity Definition represents the description of a task in the abstract, while the Task resource is used to track a specific instance of a task as it moves through the steps of a workflow.

An Activity Definition resource provides a description, or template, of an action to be performed. These actions can be purely text-based descriptions of the action to be performed, only interpretable by a human user, or they can be structured definitions with enough information to construct a resource to represent the request or activity directly. This process of converting the Activity Definition into a specific resource in a particular context is performed with the “$apply” operation.

In the simplest case, the process maps the elements specified in the Activity Definition to the corresponding elements on a resource of the appropriate type, using the kind element of the definition to determine the type of resource to be created.

More dynamic scenarios can be achieved in one of two ways, either by providing dynamic value expressions, or by specifying a Structure Map that transforms the definition into the appropriate request resource.

Note that systems will likely vary widely in the degree of support they provide for the “$apply” operation. In particular, the fact that a system supports applying definitions of one category, does not imply that it supports applying definitions for all categories. For example, a service focused on medication order sets may have sophisticated support for Medication Request activities, but no support at all for the Service Request activities.

Fast Healthcare Interoperability Resources (FHIR) is a draft standard describing data formats and elements (known as “resources”) and an application programming interface (API) for exchanging electronic health records. The standard was created by the Health Level Seven International (HL7) health-care standards organization.

Its goal is to facilitate interoperation between legacy healthcare systems, to make it easy to provide healthcare information to healthcare providers and individuals on a wide variety of devices from computers to tablets to cell phones, and to allow third-party application developers to provide medical applications which can be easily integrated into existing systems.

FHIR provides an alternative to document-centric approaches by directly exposing discrete data elements as services. For example, basic elements of healthcare like patients, admissions, diagnostic reports and medications can each be retrieved and manipulated via their own resource URLs (Uniform Resource Locators). FHIR was supported at an American Medical Informatics Association meeting by many EHR (Electronic Health Record) vendors which value its open and extensible nature.

About this Dataset

Data Info

Date Created


Last Modified




Update Frequency


Temporal Coverage


Spatial Coverage

United States


John Snow Labs; Health Level Seven International;

Source License URL

Source License Requirements


Source Citation



FHIR, HL7, Medical Terminology, Processes Data, Processes Information, Processes Documentation, Health Information Exchange, Electronic Health Records, FHIR Smart, Smart on FHIR

Other Titles

FHIR Activity Definition Resource, Electronic Health Records Exchange Through FHIR

Data Fields

Name Description Type Constraints
Concept_NameName of the concept in the FHIR structurestringrequired : 1
Computer_Ready_NameA Computer-ready name (e.g. a token) that identifies the structure - suitable for code generation. Note that this name (and other names relevant for code generation, including element & slice names, codes etc) may collide with reserved words in the relevant target language, and code generators will need to handle this.string-
TypeThe type the structure describes.string-
Dollar_RefThe Dollar_Ref ($ref) string value contains a Uniform Resource Identifier (URI) which identifies the location of the JSON (JavaScript Object Notation) value being referenced.string-
DescriptionA free text natural language description of the structure and its usestring-
ItemsThe value of the keyword should be an object or an array of objects. If the keyword value is an object, then for the data array to be valid each item of the array should be valid according to the schema in this value.string-
EnumThe enum is used to restrict a value to a fixed set of values. It must be an array with at least one element, where each element is unique.string-
RequiredThe value of the keyword should be an array of unique strings. The data object to be valid should contain all properties with names equal to the elements in the keyword value.string-
ConstThe value of this keyword can be anything. The data is valid if it is deeply equal to the value of the keyword.string-

Data Preview

Concept NameComputer Ready NameTypeDollar RefDescriptionItemsEnumRequiredConst
ActivityDefinitionresourceTypeThis is a ActivityDefinition resourceActivityDefinition
ActivityDefinitionid#/definitions/idThe logical ID of the resource as used in the URL for the resource. Once assigned this value never changes.
ActivityDefinitionmeta#/definitions/MetaThe metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.
ActivityDefinitionimplicitRules#/definitions/uriA reference to a set of rules that were followed when the resource was constructed and which must be understood when processing the content. Often this is a reference to an implementation guide that defines the special rules along with other profiles etc.
ActivityDefinition_implicitRules#/definitions/ElementExtensions for implicitRules
ActivityDefinitionlanguage#/definitions/codeThe base language in which the resource is written.
ActivityDefinition_language#/definitions/ElementExtensions for language
ActivityDefinitiontext#/definitions/NarrativeA human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.
ActivityDefinitioncontainedarrayThese resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently and nor can they have their own independent transaction scope.{'$ref': '#/definitions/ResourceList'}
ActivityDefinitionextensionarrayMay be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension there is a set of requirements that SHALL be met as part of the definition of the extension.{'$ref': '#/definitions/Extension'}