The Mapping Specialist will initiate the mapping process by evaluating the source SNOMED CT concept employing the context-free assumption: SNOMED CT concepts to be mapped from the source domains will be presumed to "speak for themselves". The concept definition as asserted in the Fully Specified Name (FSN) and the concept's defining relationships (excluding qualifiers) will be presumed to encompass all information available for definition of the concept and interpreted as explained in the SNOMED CT Editorial Guide. This information alone will be employed by the Mapping Specialist in assessing the source meaning and researching target code(s) for the MAP.

If the meaning of the SNOMED CT concept is judged to be ambiguous by the Mapping Specialist, the concept will be managed as follows.

Definition of ambiguity

Cases for concern or question of ambiguity in the SNOMED CT source concept definition will include:

1. Discrepancy between the FSN and associated defining relationships; and
2. Discordance between the SNOMED CT definition and the term synonyms.

Discrepancies will be assessed relative to standard medical references and compared to guidance and definitions provided in the ICD10 authoritative source. These two cases are described in more detail below:

Case #1 constitutes fundamental ambiguity in the meaning of the SNOMED CT concept and cannot be mapped pending clarification. These concepts will be assigned a Map member with mapCategoryId of 447640006 | Source SNOMED CT concept is ambiguous| . The editorial notes field will be populated with any information on the map accrued by the Mapping Specialists during their research. The concept will be referred to the SNOMED CT editors and the Map Lead. Once the ambiguity is resolved, the map will be completed and mapCategoryId will be updated with the appropriate assignment.

Case #2 represents a confusing issue for the Mapping Specialist using only lexical tools to review SNOMED CT and ICD10. However, the SNOMED CT definition is not truly ambiguous and the map for this concept will be completed as described herein. The SNOMED CT term which is the source of the confusion will be flagged by the Mapping Team in the editor's notes for editorial review with the expectation that the confusing term will be marked for demotion as a non-synonymous lexical tag.

Examples of Case #2, Discrepancy in synonyms:

• SNOMED CT 95531001 | Hemorrhagic duodenitis (disorder)|  has a synonym  95531001 | multiple duodenal erosions|  (Description.id: 512170014) and definition as a hemorrhagic inflammation of duodenal structure. The synonym implies ulceration and not hemorrhage and should likely be defined and classified as a type of duodenal ulcer.

  95531001 | Hemorrhagic duodenitis(disorder)|  maps to ICD10 classification K29.8, Duodenitis. Discrepancy with concept definition will cause the Mapping Specialist to report the concept  95531001 | Hemorrhagic duodenitis (disorder)|  as confusing and in need of editorial review.

The context-free assumption will require agreement regarding procedures for the map when certain elements of mapping context are asserted in either the SNOMED CT source or the ICD10 target reference. These context issues, along with mappings to multiple target codes, are detailed in the following section. In all discussions, source always refers to the SNOMED CT concept and target refers to the ICD10 classification.