Inactivation ReasonAssociation TypeDescription

Ambiguous

“POSSIBLY_EQUIVALENT_TO”

This inactivation reason explicitly states that the inactivated concept is inherently ambiguous but that each of the potential meanings represented by the ambiguous concept is semantically identical to one of the “POSSIBLY_EQUIVALENT_TO” target concepts, whether currently present or could be created in SNOMED CT.

The implication of this definition is that for any given ambiguous concept there must be 2 or more POSSIBLY_EQUIVALENT_TO target concepts.

Guidance

Identify ALL possible meanings that arise from the ambiguity. Identify semantically equivalent SCT concepts where they exist, and create new concepts where they do not exist.

  • Non or partial synonymous synonyms
    Resolve these by inactivation as "Not semantically equivalent component' and the association type of "REFERS_TO" reassigning the description to either an existing concept or if necessary creating a new concept.
  • Classification concepts
    If the concept's ambiguity results from a classification disjunction or conjunction, use the inactivation reason of "Classification concept".
  • Incorrect modeling
    Where the modeling of the concept is at variance with the meaning of the FSN, correct the modeling - this advice may change once the QI project has been completed and ECL is widely used.

  • Additional notes:

    1. Identifying true ambiguity rather than lack of specificity or the meaning is "not known" and resolving the full suite of POSSIBLT_EQUIVALENT_To target concepts can sometimes be difficult.
    2. Share difficult ambiguous inactivations in the internal editor's meetings
    3. It is possible that one of the interpretations of the ambiguity gives rise to a concept that is not clinically meaningful. It is still important to create a concept to represent this concept to ensure that there is full semantic equivalence between the sum of the POSSIBLY_EQUIVALENT_TO targets and the ambiguous concept being inactivated as this is the only way of supporting analysis of historically coded clinical data that may have used the ambiguous concept. As a secondary action, the concept that is not clinically meaningful may then itself be inactivated.

Examples


Multiple possible meanings:

  •  has 3 possible meanings all of which exist within SNOMED CT:


Resolution:

  • Inactivate 269530002 |Ca lesser curvature - stomach (disorder)| with the following target historical associations:
    • POSSIBLY_EQUIVALENT_TO 
    • POSSIBLY_EQUIVALENT_TO 


    • POSSIBLY_EQUIVALENT_TO


Two possible meanings:

       has 2 possible meanings one of which does not exist within SNOMED CT:

  • Polycystic ovary syndrome - available in SCT 
  • Polycystic ovary - did not exist in SCT

Resolution:

  • Create a new concept: Polycystic ovary
  • Inactivate 69878008 |Polycystic ovaries (disorder)| with the following target historical associations:
    • POSSIBLY_EQUIVALENT_TO 
    • POSSIBLY_EQUIVALENT_TO 

Managing Incoming Historical Associations


The intention is that this functionality will be seamlessly integrated into the tooling so as to present to the user the appropriate updated historically association to be allocated.

Whenever an already stated POSSIBLY_EQUIVALENT_TO target itself also becomes inactive - whether at the same release or later, identifying the replacement for the original concept, should follow the combinatorial logic stated below.

(A) POSSIBLY_EQUIVALENT_TO (B OR C) and (B) SAME_AS (D) implies A POSSIBLY_EQUIVALENT_TO (C OR D)

(A) POSSIBLY_EQUIVALENT_TO (B OR C) and (B) REPLACED_BY (D) implies (A) POSSIBLY_EQUIVALENT_TO (C OR D)

(AIntEd) POSSIBLY_EQUIVALENT_TO (BIntEd OR CIntEd) and (BIntEd) MOVED_TO (DNRC) implies (AIntEd) POSSIBLY_EQUIVALENT_TO (CIntEd)

(A) POSSIBLY_EQUIVALENT_TO (B OR C) and (B) POSSIBLY_EQUIVALENT_TO (D OR E) implies A POSSIBLY_EQUIVALENT_TO (C OR D OR E)

(A) POSSIBLY_EQUIVALENT_TO (B OR C) and (B) WAS_A (D AND E) implies ((A) POSSIBLY_EQUIVALENT_TO (C) OR (A) WAS_A (D AND E))