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. 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. If the element is present, it must have either a @value, an @id, or extensions 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 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. 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. 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. Indicates the mechanism used to compare versions to determine which CodeSystem is more current. 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. A short, descriptive, user-friendly title for the code system. The status of this code system. Enables tracking the life-cycle of the content. A Boolean value to indicate that this code system is authored for testing purposes (or education/evaluation/marketing) and no version of this resource will ever be intended for genuine usage. The date (and optionally time) when the code system was last significantly changed. 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. The name of the organization or individual responsible for the release and ongoing maintenance of the code system. Contact details to assist a user in finding and communicating with the publisher. A free text natural language description of the code system from a consumer's perspective. 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. A legal or geographic region in which the authority that maintains the resource is operating. In general, the jurisdiction is also found in the useContext. The useContext may reference additional jurisdictions because the defining jurisdiction does not necessarily limit the jurisdictions of use. Explanation of why this code system is needed and why it has been designed as it has. A copyright statement relating to the code system and/or its contents. Copyright statements are notices of intellectual property ownership and can include restrictions on the use and publishing of the code system. A short string (<50 characters), suitable for inclusion in a page footer that identifies the copyright holder, effective period, and optionally whether rights are restricted. (e.g. 'All rights reserved', 'Some rights reserved'). The date on which the resource content was approved by the publisher. Approval happens once when the content is officially approved for usage. The date on which the resource content was last reviewed. Review happens periodically after approval but does not change the original approval date. The period during which the CodeSystem content was or is planned to be in active use. Descriptions related to the content of the CodeSystem. Topics provide a high-level categorization as well as keywords for the CodeSystem that can be useful for filtering and searching. An individiual or organization primarily involved in the creation and maintenance of the CodeSystem. An individual or organization primarily responsible for internal coherence of the CodeSystem. An individual or organization asserted by the publisher to be primarily responsible for review of some aspect of the CodeSystem. An individual or organization asserted by the publisher to be responsible for officially endorsing the CodeSystem for use in some setting. Related artifacts such as additional documentation, justification, dependencies, bibliographic references, and predecessor and successor artifacts. If the type is `successor` or `predecessor`, the related resource must be a CodeSystem. If code comparison is case sensitive when codes within this system are compared to each other. Canonical reference to the value set that contains all codes in the code system independent of code status. The meaning of the hierarchy of concepts as represented in this resource. The code system defines a compositional (post-coordination) grammar. 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. The extent of the content of the code system (the concepts and codes it defines) are represented in this resource instance. The canonical URL of the code system that this code system supplement is adding designations and properties to. 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. A filter that can be used in a value set compose statement when selecting concepts using a filter. A property defines an additional slot through which additional information can be provided about a concept. 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. 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. The code that identifies this filter when it is used as a filter in [ValueSet](valueset.html#).compose.include.filter. A description of how or why the filter is used. A list of operators that can be used with the filter. A description of what the value for the filter should be. 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. 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. Reference to the formal meaning of the property. One possible source of meaning is the [Concept Properties](codesystem-concept-properties.html) code system. A description of the property- why it is defined, and how its value might be used. 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). 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. A code - a text symbol - that uniquely identifies the concept within the code system. A human readable string that is the recommended default way to present this concept to a user. 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. Additional representations for the concept - other languages, aliases, specialized purposes, used for particular purposes, etc. A property value for this concept. Defines children of a concept to produce a hierarchy of concepts. The nature of the relationships is variable (is-a/contains/categorizes) - see hierarchyMeaning. 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. The language this designation is defined for. A code that details how this designation would be used. Additional codes that detail how this designation would be used, if there is more than one use. The text value for this designation. 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. A code that is a reference to CodeSystem.property.code or is a code from [http://hl7.org/fhir/concept-properties](codesystem.html#defined-props) in the case that there is no corresponding code defined in `CodeSystem.property.code`. The value of this property. Equals Is A (by subsumption) Descendent Of (by subsumption) Not (Is A) (by subsumption) Regular Expression In Set Not in Set Generalizes (by Subsumption) Child Of Descendent Leaf Exists If the element is present, it must have either a @value, an @id, or extensions code (internal reference) Coding (external reference) string integer boolean dateTime decimal If the element is present, it must have either a @value, an @id, or extensions Grouped By Is-A Part Of Classified With If the element is present, it must have either a @value, an @id, or extensions Not Present Example Fragment Complete Supplement If the element is present, it must have either a @value, an @id, or extensions