Purpose

Reference set members can be added within an extension for a variety of reasons, including:

• To add members to a subset in the extension that is used nationally or locally

• To adapt a reference set created by another organization, by adding new members that are required nationally or locally

Principles

Specifying members of a reference set can be done in different ways. It will depend on the requirements for the reference set what approach is feasible and possible. Please refer to the Practical Guide to Reference Sets for detailed instructions on the and for identifying the SNOMED CT components that will be referenced by the members of the reference set.

However, each reference set member will be represented in the reference set in accordance with the following principles and process.

Reference set members may be added to reference sets belonging to modules in

• The producers extension

• The International Edition

• Other extensions (which the producers extension modules are dependent on)

Reference set members created in the extension should be created within the module of the extension producer, so that it is possible to distinguish the reference set members created within the producers extension from reference set members created by other organisations (i.e. belonging to other modules).

Even though the individual reference set members belong to the module of the extension producer, the actual components that are referenced by the reference set member, may belong to modules in

• The International Edition

• The extension in which the reference set and its members are produced

• Other extensions (which the producers extension modules are dependent on)

The table below provides a summary of the process to follow when adding members to a reference set.

Purpose

There are a number of reasons for modifying members of a reference set in an extension (depending on the type of reference set), including:

• Updating map records to

  • Refine map rules or map advice

  • Change the target of a map

• Changing the acceptability of a description in a language reference set

• Changing the order of subset members specified in an

Principles for modifying reference sets include:

• Reference sets can be modified by

  • Adding or inactivating reference set members. Please refer to the guidance on or .

  • Modifying mutable attribute values of reference set members. To see what attributes are mutable for each reference set type, please refer to the specification of the specific reference set type in the . If the reference set type is a locally defined reference set, please consider any mutability constraints on the individual attributes.

The table below provides a summary of the process to follow when modifying an existing member in a Reference Set.

Table: Modify reference set member

Purpose

Reference set members may be inactivated when

• The reference set member is no longer relevant or valid in the reference set in which it is being used

• The reference set to which the reference set member belongs is inactivated

Principles

Any inactivation of reference set members should be done in the module of the reference set producer.

Process

The table below provides a summary of the process to follow when removing members from a reference set.

Reference set members may also be added, modified or inactivated in an extension, to meet evolving requirements.

The sections that follow will examine the purpose, principles and process for each of these authoring tasks.