Purpose

The  is designed to enable associations between code in another code system  and , where the following constraints apply:

  1. Some of the  cannot be mapped to an individual SNOMED CT .
  2. Licensing conditions (or other considerations) prevent addition of new SNOMED CT concepts to represent the same meaning as the .
  3. The  can be logically defined using the  to represent the same meaning  or a similar though less specific meaning .
  4. Other requirements similar for those applicable to mapping may also apply including:
    1. An indication of the degree of correlation between the   and the SNOMED CT expression.
    2. An indication of whether the  was created before any single concept representation of that meaning in SNOMED CT or whether the single concept representation in SNOMED CT predated the creation of the association.

Data Structure

The general approach to the above requirements is to associate each of the  with a representation of the same logic based definition as would have been applied to a SNOMED CT concept with that meaning. However, since the   are not identified by an  , the logical definition cannot be represented using  . There are two potential approaches to this, one would be to use a general purpose description logic language (e.g.  ) and the other is to use a  to represent each definition. The  is designed to support the expression-based approach.


Field

Data type

Purpose

Part of Primary Key

id

A 128 bit unsigned , uniquely identifying this .

Different versions of a reference set member share the same but have different . This allows a reference set member to be modified or made (i.e. removed from the active set) at a specified time.

NO

YES (Full/Snapshot) 

The inclusive date or time at which this version of the identified became the current version.

The current version of this at time T is the version with the most recent prior to or equal to time T .

YES

YES (Full)

Optional (Snapshot) 

The state of the identified as at the specified .

If = 1 (true) the is part of the current version of the set, if = 0 (false) the is not part of the current version of the set.

YES

NO

Identifies the that contains this as at the specified .

The value must be a of within the metadata .

YES

NO

Identifies the to which this belongs.

In this case, set to as subtype descendant of:

NONO

A reference to the to be included in the .

NONO

The to/from which the concept is mapped.

NONO

A   that represents the SNOMED CT definition of the  . This expression may be a   or   of the definition provided that documentation of each identified reference set specifies the view provided.

The expression must conform to the syntax defined in the SNOMED CT Compositional Grammar - Specification and Guide (http://snomed.org/scg).

YESNO


Indicates whether or not the expression contains a sufficient definition of the in the mapTarget field.
Possible values are the following subtypes of :

    900000000000074008 |Necessary but not sufficient concept definition status|
    900000000000073002 |Sufficiently defined concept definition status|


YESNO

The correlation between the SNOMED CT expression and the . Possible values are the following subtypes of :

	447559001 |Broad to narrow map from SNOMED CT source code to target code|
	447557004 |Exact match map from SNOMED CT source code to target code|
	447558009 |Narrow to broad map from SNOMED CT source code to target code|
	447560006 |Partial overlap between SNOMED CT source code and target code|

When these values are applied to this reference set type, the phrase "SNOMED source code" is interpreted as meaning "SNOMED expression" and "target code" refers to the .

YESNO

Indication of whether the concept was initially in one of the terminologies (SNOMED CT or ) and added to the other as part of mapping or was in both terminologies at the outset. Values are subtypes of  .

YESNO


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