Once the Map Terminologists review and understand the SNOMED CT source concept to be mapped, they employ the ICD-10 alphabetic index to search and select candidate ICD-10 target codes for the map. They research the Fully Specified Name from the SNOMED CT source concept searching the best textual references in the alphabetic index that capture the meaning of the SNOMED CT concept. The WHO alphabetic index lists multiple term modifiers that can be considered as specifications or qualifiers of the primary term, and the Map Terminologist will search through the specifications looking for the relevant terms of interest.
This review may identify matching ICD-10 terms or may require searching through related cross-references. Two types of cross-reference in the ICD-10 alphabetic index must be considered before assignment of a tentative target code(s). These are: '-see…', and '-see also…'.
This is an explicit direction to look elsewhere in the index, and no codes are found alongside this reference. The Map Terminologist will review the directed descriptions in searching for target candidates.
Nodule(s), nodular
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This reference instructs the user to look elsewhere if the detail (s)he is looking for cannot be determined from the current reference.
Hyperbilirubinemia
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When a code is given alongside the term showing the '-see also…' appearing in parentheses as in the above example, it may or may not be necessary to look under the alternative term.
When no code is given, the instruction does not appear in parentheses as it is essential for the user to look under the alternative lead term. In the following example with reference to the term "Enlargement", the Map Terminologist must also evaluate the alpha references for "Hypertrophy" for relevant target classifications.
Enlargement, enlarged
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The Map Terminologist will create preliminary Map members employing the candidate target records resulting from these searches. If specializations are noted in targets selected from the alphabetic index and there exist sub-headings for the term selected, these will be considered for exclusion rules as documented in section 6.9. Mapping Context - Exclusions, Alpha Modifiers and Co-morbidities. For source concepts that represent examples of poisonings caused by drugs or chemicals, the Map Terminologist will use section III of the Alphabetic Index: Table of Drugs and Chemicals to research the default maps and essential modifiers. An example of this is provided in section 6.9.
The Map Terminologist will proceed from this source concept analysis to research the tabular guidance for the candidate targets and evaluate for issues of mapping context which may alter the Map members as explained in the following sections 6.3. through 6.11.