Background

SNOMED CT is a clinical terminology with global scope covering a wide range of clinical specialties and requirements. To support the implementation of SNOMED CT, there is often a need to create maps from current in-use, local and proprietary code systems to SNOMED CT. Similarly, there is often a need to create maps from SNOMED CT to classifications and reporting code systems to support reporting, billing and statistical purposes.

What is a map?

A map is a collection of associations between codes, concepts or terms in one code set (the 'source') to codes, concepts or terms in another code set (the 'target') that have the same (or similar) meanings.

Maps are developed in accordance with a documented rationale, for a given purpose and as a result there may be different maps between the same pair of code systems to meet different uses cases.

A code set can be

• A list of codes and/or terms
• A vocabulary
• A terminology

A map is often published as a table but can also be published in RF2 as a map reference set or a FHIR ConceptMap.

What is mapping?

Mapping is the process of defining a relationship between the source and target codes, concepts or terms.

Purpose

The SNOMED CT Mapping Guide describes the best practice and guidelines for mapping between other code systems and SNOMED CT. Specialized mapping guidance designed for specific source and target code systems are available in other documents. For example, the ICD-10 Mapping Technical Guide.

Audience

The target audience of this document includes any users who are involved in the mapping process including

• SNOMED CT National Release Centers;
• eHealth system designers and developers, including designers and developers of EHR systems, information models, data entry interfaces, storage systems, decision support systems, retrieval and analysis systems, communication standards and terminology services;
• SNOMED CT terminology developers, including concept model designers, content authors, map developers and release process managers.