> 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-postcoordination-guide/snomed-ct-expressions/use-cases.md).

# Use Cases

There is a range of use cases in which it **may** be helpful to use postcoordination, including:

**Capture new clinical meanings in a health record, message structure, or query specification**

* To support situations where clinicians need to record and share a clinical meaning, which has not been defined in any release of SNOMED CT. This applies to direct data entry, coding values in UIs, or other clinical situations. SNOMED CT postcoordinated expressions can be used to represent a new clinical meaning as an alternative to concept authoring.

**Enable interoperability between different structural representations of the same clinical meaning**

* To support transformation between different representations within a clinical system or while exchanging data between systems. The postcoordinated expression is a common representation of clinical meaning. It can be exchanged and compared between models and shared as part of interoperability standards like HL7 FHIR.

**Represent maps from other code systems or from interface terms to an equivalent representation of the meaning in SNOMED CT**

* To map other code systems to SNOMED CT may require the representation of new meanings or combinations of meanings already represented in SNOMED CT. In these cases, when a suitable precoordinated concept is not available, postcoordination offers an alternative to concept authoring.

**Support Natural Language Processing**

* To transform the meaning of free text into structured SNOMED CT expressions. Postcoordination allows the representation of specific context or a greater amount of detail in the free text than you can capture with a single precoordinated code

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