Code System

$10 / year

The Code System 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.

Complexity

The FHIR (Fast Healthcare Interoperability Resources) terminology specification is based on two key concepts:

– code system – declares the existence of and describes a code system or code system supplement and its key properties, and optionally defines a part or all of its content. Also known as Ontology, Terminology, or Enumeration
– value set – specifies a set of codes drawn from one or more code systems, intended for use in a particular context. Value sets link between CodeSystem definitions and their use in coded elements

Code systems define which codes (symbols and/or expressions) exist, and how they are understood. Value sets select a set of codes from one or more code systems to specify which codes can be used in a particular context.

The CodeSystem resource is used to declare the existence of a code system, and its key properties:

– Identifying URL and version
– Description, Copyright, publication date, and other metadata
– Some key properties of the code system itself – e.g. whether it exhibits concept permanence, whether it defines a compositional grammar, and whether the codes that it defines are case sensitive
– What filters can be used in value sets that use the code system in a ValueSet.compose element
– What concept properties are defined by the code system
– In addition, the CodeSystem resource may list some or all of the concepts in the code system, along with their basic properties (code, display, definition), designations, and additional properties. Code System resources may also be used to define supplements, which extend an existing code system with additional designations and properties.

The CodeSystem resource is not intended to support the process of maintaining code systems. Instead, the focus is on publishing the properties and optionally the content of a code system for use throughout the FHIR eco-system, such as to support value set expansion and validation. Note that the important existing (large) code systems (SNOMED CT, LOINC, RxNorm, ICD family, etc.) all have their own maintenance systems and distribution formats, and CodeSystem is generally not an efficient way to distribute their content, though it is used as one way of declaring the filters and properties associated with those code systems.

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.

Date Created

2018-09-20

Last Modified

2019-11-01

Version

4.0.1

Update Frequency

Annual

Temporal Coverage

N/A

Spatial Coverage

United States

Source

John Snow Labs; Health Level Seven International;

Source License URL

Source License Requirements

N/A

Source Citation

N/A

Keywords

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

Other Titles

FHIR Code System Resource, Electronic Health Records Exchange Through FHIR

NameDescriptionTypeConstraints
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-
Concept NameComputer Ready NameTypeDollar RefDescriptionItemsEnumRequiredConst
CodeSystemresourceTypeThis is a CodeSystem resourceCodeSystem
CodeSystemid#/definitions/idThe logical id of the resource as used in the URL for the resource. Once assigned this value never changes.
CodeSystemmeta#/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.
CodeSystemimplicitRules#/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.
CodeSystem_implicitRules#/definitions/ElementExtensions for implicitRules
CodeSystemlanguage#/definitions/codeThe base language in which the resource is written.
CodeSystem_language#/definitions/ElementExtensions for language
CodeSystemtext#/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.
CodeSystemcontainedarrayThese 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'}
CodeSystemextensionarrayMay 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'}
Related Data Packages