> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-mapping-guide/map-development/9-mapping-to-snomed-ct.md). # Mapping to SNOMED CT ## Defining the map scope SNOMED CT contains a number of hierarchies, each representing different types of concepts. When mapping to SNOMED CT, it's important to understand the scope of the source content that you are mapping so you can define the SNOMED CT scope appropriately. When mapping to SNOMED CT, you should constrain the target scope to a specific hierarchy, subhierarchy or subset of SNOMED CT. This will improve the accuracy of any automated mapping tools you may be using and reduce the risk of errors caused by users developing the map. #### Example scopes: {% hint style="info" %} If you are mapping a type of organ or body site, then the map scope might be the ‘Body structure’ hierarchy ( < 123037004 |Body structure (body structure)|) {% endhint %} {% hint style="info" %} If you're mapping conditions, judgements or assessments about a patient, the scope might be the Clinical finding hierarchy ( < 404684003 |Clinical finding (finding)|) {% endhint %} ## Mapping process During the map process, once the target scope has been defined to the appropriate hierarchy, subhierarchy or subset of SNOMED CT, authors and reviewers can then search for an appropriate code to map to. When selecting a code, the user must review the concept’s Fully Specified Name and defining relationships to understand the intended meaning of each concept, and use the use case and rules of the map (such as requirements for equivalence, allowance for 1:many maps, context of implementation, etc) to determine what is an appropriate match. An example process a user may conduct is: * search SNOMED CT for a matching concept * find an appropriate candidate concept * assign it to the source code with a relationship type There may be instances where there is more than one candidate concept; depending on the map's rules, it may be appropriate to select more than one. It may also be appropriate to select the most general supertype concept that completely matches the required semantics. Where there are no appropriate SNOMED CT concepts available, it may be appropriate to * Create or request an appropriate pre-coordinated concept in an extension to be used in the map * Use a SNOMED CT postcoordinated expression that captures the requirements, if the use case of the map can support this * Define the map as having no map target Provide Feedback --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-mapping-guide/map-development/9-mapping-to-snomed-ct.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.