An indication of whether the value of an attribute can change between two released versions of the same component.
All released versions of the same component have the same identifier (id) but each version has a different effectiveTime. If a field is mutable (Mutable=YES), its value can differ from one version to the next without the identifier changing. If a field is Immutable (Mutable=NO), its value must be the same in every version of a specific identified component. If the value associated with an immutable field needs to be changed, the existing component must be inactivated and a new component must be created to replace it. The new component must have a previously unused identifier its field values must be set to replace the inactivated concept with the updated information.
The mutability for each field (or column) in each type of release file is indicated in the release file specification table for that component type or reference set (see SNOMED CT Release File Specifications).
- Immutable (opposite of mutable)