FHIR R4 CodeSystem Library

Overview

This asset is a component of MuleSoft Accelerator for Healthcare.

MuleSoft Accelerator for Healthcare enables healthcare providers to unlock critical patient data to build a patient 360 within Salesforce Health Cloud, faster and easier than ever before. The solution includes pre-built APIs, connectors, integration templates, and a prescriptive end-to-end reference architecture to bring patient demographics information and COVID-19 test results from any EHR into Health Cloud using HL7 V2 or FHIR standards.

The solution also provides a library of United States Core Data for Interoperability (USCDI) and FHIR R4 resources to help healthcare developers adhere to interoperability needs and jumpstart the development of healthcare digital transformation initiatives.

Use case covered

The FHIR terminology specification is based on two key concepts, originally defined in HL7 v3 Core Principles :

• 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.

This library is used by FHIR R4 CodeSystem API.

More information about FHIR R4 CodeSystem specification can be found here.