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CodeSystem

The CodeSystem resource is used to declare the existence of and describe a code system or code system supplement and its key properties, and optionally define a part or all of its content.

Elements

NameRequiredTypeDescription
urluri

Canonical identifier for this code system, represented as a URI (globally unique) (Coding.system)

Details

An absolute URI that is used to identify this code system when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which at which an authoritative instance of this code system is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the code system is stored on different servers. This is used in [Coding](datatypes.html#Coding).system.

Can be a urn:uuid: or a urn:oid: but real http: addresses are preferred. Multiple instances may share the same URL if they have a distinct version. The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in [Technical and Business Versions](resource.html#versions). In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the [meta.source](resource.html#meta) element to indicate where the current master source of the resource can be found.

identifierIdentifier[]

Additional identifier for the code system (business identifier)

Details

A formal identifier that is used to identify this code system when it is represented in other formats, or referenced in a specification, model, design or an instance.

Typically, this is used for identifiers that can go in an HL7 V3 II (instance identifier) data type, and can then identify this code system outside of FHIR, where it is not possible to use the logical URI. Note that HL7 defines at least three identifiers for many of its code systems - the FHIR canonical URL, the OID and the V2 Table 0396 mnemonic code.

versionstring

Business version of the code system (Coding.version)

Details

The identifier that is used to identify this version of the code system when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the code system author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence. This is used in [Coding](datatypes.html#Coding).version.

There may be different code system instances that have the same identifier but different versions. The version can be appended to the url in a reference to allow a reference to a particular business version of the code system with the format [url]|[version].

namestring

Name for this code system (computer friendly)

Details

A natural language name identifying the code system. This name should be usable as an identifier for the module by machine processing applications such as code generation.

The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.

titlestring

Name for this code system (human friendly)

Details

A short, descriptive, user-friendly title for the code system.

This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.

statuscode

draft | active | retired | unknown

Details

The date (and optionally time) when the code system resource was created or revised.

Allows filtering of code systems that are appropriate for use versus not.

experimentalboolean

For testing purposes, not real usage

Details

A Boolean value to indicate that this code system is authored for testing purposes (or education/evaluation/marketing) and is not intended to be used for genuine usage.

Allows filtering of code systems that are appropriate for use versus not.

datedateTime

Date last changed

Details

The date (and optionally time) when the code system was published. The date must change when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the code system changes.

Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the code system. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

publisherstring

Name of the publisher (organization or individual)

Details

The name of the organization or individual that published the code system.

Usually an organization but may be an individual. The publisher (or steward) of the code system is the organization or individual primarily responsible for the maintenance and upkeep of the code system. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the code system. This item SHOULD be populated unless the information is available from context.

contactContactDetail[]

Contact details for the publisher

Details

Contact details to assist a user in finding and communicating with the publisher.

May be a web site, an email address, a telephone number, etc.

descriptionmarkdown

Natural language description of the code system

Details

A free text natural language description of the code system from a consumer's perspective.

This description can be used to capture details such as why the code system was built, comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the code system as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context (e.g. the language of the code system is presumed to be the predominant language in the place the code system was created).

useContextUsageContext[]

The context that the content is intended to support

Details

The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate code system instances.

When multiple useContexts are specified, there is no expectation that all or any of the contexts apply.

jurisdictionCodeableConcept[]

Intended jurisdiction for code system (if applicable)

Details

A legal or geographic region in which the code system is intended to be used.

It may be possible for the code system to be used in jurisdictions other than those for which it was originally designed or intended.

purposemarkdown

Why this code system is defined

Details

Explanation of why this code system is needed and why it has been designed as it has.

This element does not describe the usage of the code system. Instead, it provides traceability of ''why'' the resource is either needed or ''why'' it is defined as it is. This may be used to point to source materials or specifications that drove the structure of this code system.

copyrightmarkdown

Use and/or publishing restrictions

Details

A copyright statement relating to the code system and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the code system.

... Sometimes, the copyright differs between the code system and the codes that are included. The copyright statement should clearly differentiate between these when required.

caseSensitiveboolean

If code comparison is case sensitive

Details

If code comparison is case sensitive when codes within this system are compared to each other.

If this value is missing, then it is not specified whether a code system is case sensitive or not. When the rule is not known, Postel's law should be followed: produce codes with the correct case, and accept codes in any case. This element is primarily provided to support validation software.

valueSetcanonical

Canonical reference to the value set with entire code system

Details

Canonical reference to the value set that contains the entire code system.

The definition of the value set SHALL include all codes from this code system and only codes from this code system, and it SHALL be immutable.

hierarchyMeaningcode

grouped-by | is-a | part-of | classified-with

Details

The meaning of the hierarchy of concepts as represented in this resource.

Note that other representations might have a different hierarchy or none at all, and represent the information using properties.

compositionalboolean

If code system defines a compositional grammar

Details

The code system defines a compositional (post-coordination) grammar.

Note that the code system resource does not define what the compositional grammar is, only whether or not there is one.

versionNeededboolean

If definitions are not stable

Details

This flag is used to signify that the code system does not commit to concept permanence across versions. If true, a version must be specified when referencing this code system.

Best practice is that code systems do not redefine concepts, or that if concepts are redefined, a new code system definition is created. But this is not always possible, so some code systems may be defined as 'versionNeeded'. Most code systems occasionally refine the displays defined for concepts between versions. Contexts in which the concept display values are validated may require that the version be specified for some code systems irrespective of the value of this property.

contentcode

not-present | example | fragment | complete | supplement

Details

The extent of the content of the code system (the concepts and codes it defines) are represented in this resource instance.

supplementscanonical

Canonical URL of Code System this adds designations and properties to

Details

The canonical URL of the code system that this code system supplement is adding designations and properties to.

The most common use of a code system supplement is to add additional language support.

countunsignedInt

Total concepts in the code system

Details

The total number of concepts defined by the code system. Where the code system has a compositional grammar, the basis of this count is defined by the system steward.

The count of concepts defined in this resource cannot be more than this value but may be less for several reasons - see the content element.

filterCodeSystemfilter[]

Filter that can be used in a value set

Details

A filter that can be used in a value set compose statement when selecting concepts using a filter.

Note that filters defined in code systems usually require custom code on the part of any terminology engine that will make them available for use in value set filters. For this reason, they are generally only seen in high value published terminologies.

idstring

Unique id for inter-element referencing

Details

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

extensionExtension[]

Additional content defined by implementations

Details

May be used to represent additional information that is not part of the basic definition of the element. 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored even if unrecognized

Details

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

codecode

Code that identifies the filter

Details

The code that identifies this filter when it is used as a filter in [ValueSet](valueset.html#).compose.include.filter.

descriptionstring

How or why the filter is used

Details

A description of how or why the filter is used.

operatorcode[]

= | is-a | descendent-of | is-not-a | regex | in | not-in | generalizes | exists

Details

A list of operators that can be used with the filter.

valuestring

What to use for the value

Details

A description of what the value for the filter should be.

propertyCodeSystemproperty[]

Additional information supplied about each concept

Details

A property defines an additional slot through which additional information can be provided about a concept.

idstring

Unique id for inter-element referencing

Details

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

extensionExtension[]

Additional content defined by implementations

Details

May be used to represent additional information that is not part of the basic definition of the element. 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored even if unrecognized

Details

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

codecode

Identifies the property on the concepts, and when referred to in operations

Details

A code that is used to identify the property. The code is used internally (in CodeSystem.concept.property.code) and also externally, such as in property filters.

uriuri

Formal identifier for the property

Details

Reference to the formal meaning of the property. One possible source of meaning is the [Concept Properties](codesystem-concept-properties.html) code system.

descriptionstring

Why the property is defined, and/or what it conveys

Details

A description of the property- why it is defined, and how its value might be used.

typecode

code | Coding | string | integer | boolean | dateTime | decimal

Details

The type of the property value. Properties of type "code" contain a code defined by the code system (e.g. a reference to another defined concept).

conceptCodeSystemconcept[]

Concepts in the code system

Details

Concepts that are in the code system. The concept definitions are inherently hierarchical, but the definitions must be consulted to determine what the meanings of the hierarchical relationships are.

If this is empty, it means that the code system resource does not represent the content of the code system.

idstring

Unique id for inter-element referencing

Details

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

extensionExtension[]

Additional content defined by implementations

Details

May be used to represent additional information that is not part of the basic definition of the element. 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored even if unrecognized

Details

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

codecode

Code that identifies concept

Details

A code - a text symbol - that uniquely identifies the concept within the code system.

displaystring

Text to display to the user

Details

A human readable string that is the recommended default way to present this concept to a user.

definitionstring

Formal definition

Details

The formal definition of the concept. The code system resource does not make formal definitions required, because of the prevalence of legacy systems. However, they are highly recommended, as without them there is no formal meaning associated with the concept.

designationCodeSystemconceptdesignation[]

Additional representations for the concept

Details

Additional representations for the concept - other languages, aliases, specialized purposes, used for particular purposes, etc.

Concepts have both a ```display``` and an array of ```designation```. The display is equivalent to a special designation with an implied ```designation.use``` of "primary code" and a language equal to the [Resource Language](resource.html#language).

idstring

Unique id for inter-element referencing

Details

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

extensionExtension[]

Additional content defined by implementations

Details

May be used to represent additional information that is not part of the basic definition of the element. 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored even if unrecognized

Details

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

languagecode

Human language of the designation

Details

The language this designation is defined for.

In the absence of a language, the resource language applies.

useCoding

Details how this designation would be used

Details

A code that details how this designation would be used.

If no use is provided, the designation can be assumed to be suitable for general display to a human user.

valuestring

The text value for this designation

Details

The text value for this designation.

propertyCodeSystemconceptproperty[]

Property value for the concept

Details

A property value for this concept.

idstring

Unique id for inter-element referencing

Details

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

extensionExtension[]

Additional content defined by implementations

Details

May be used to represent additional information that is not part of the basic definition of the element. 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored even if unrecognized

Details

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

codecode

Reference to CodeSystem.property.code

Details

A code that is a reference to CodeSystem.property.code.

value[x]code, Coding, string, integer, boolean, dateTime, decimal

Value of the property for this concept

Details

The value of this property.

concept[]

Child Concepts (is-a/contains/categorizes)

Details

Defines children of a concept to produce a hierarchy of concepts. The nature of the relationships is variable (is-a/contains/categorizes) - see hierarchyMeaning.

Search Parameters

NameTypeDescriptionExpression
contexttoken A use context assigned to the code system CodeSystem.useContext.value as CodeableConcept
context-quantityquantity A quantity- or range-valued use context assigned to the code system CodeSystem.useContext.value as Quantity | CodeSystem.useContext.value as Range
context-typetoken A type of use context assigned to the code system CodeSystem.useContext.code
datedate The code system publication date CodeSystem.date
descriptionstring The description of the code system CodeSystem.description
jurisdictiontoken Intended jurisdiction for the code system CodeSystem.jurisdiction
namestring Computationally friendly name of the code system CodeSystem.name
publisherstring Name of the publisher of the code system CodeSystem.publisher
statustoken The current status of the code system CodeSystem.status
titlestring The human-friendly name of the code system CodeSystem.title
urluri The uri that identifies the code system CodeSystem.url
versiontoken The business version of the code system CodeSystem.version
context-type-quantitycomposite A use context type and quantity- or range-based value assigned to the code system CodeSystem.useContext
context-type-valuecomposite A use context type and value assigned to the code system CodeSystem.useContext
codetokenA code defined in the code systemCodeSystem.concept.code
content-modetokennot-present | example | fragment | complete | supplementCodeSystem.content
identifiertoken External identifier for the code system CodeSystem.identifier
languagetokenA language in which a designation is providedCodeSystem.concept.designation.language
supplementsreferenceFind code system supplements for the referenced code systemCodeSystem.supplements
systemuriThe system for any codes defined by this code system (same as 'url')CodeSystem.url

Inherited Elements

NameRequiredTypeDescription
idstring

Logical id of this artifact

Details

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

metaMeta

Metadata about the resource

Details

The 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.

implicitRulesuri

A set of rules under which this content was created

Details

A 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.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

languagecode

Language of the resource content

Details

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

textNarrative

Text summary of the resource, for human interpretation

Details

A 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.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

containedResource[]

Contained, inline Resources

Details

These 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.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

extensionExtension[]

Additional content defined by implementations

Details

May 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.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

modifierExtensionExtension[]

Extensions that cannot be ignored

Details

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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 is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.