6.2. Choosing Initial Target Codes

Once the Mapping Specialists have reviewed and understand the SNOMED CT source concept to be mapped, they will employ the ICD-10 alphabetic index to search and select candidate ICD-10 target codes for the map. They will 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 Mapping Specialist will search through the specifications looking for the relevant terms of interest.

This review may identify matching ICD-10 terms, or may require searching though related cross references. Two types of cross-reference in the WHO alphabetic listing must be considered before assignment of a tentative target code(s). These are: '-see…', and '-see also…'.

• '-see…' is an explicit direction to look elsewhere in the index and no codes are found alongside this reference. The Mapping Specialist will review the directed descriptions in searching for target candidates.

  Nodule(s), nodular

• subcutaneous - see Swelling, localized|

• '-see also…' instructs the user to look elsewhere if the detail they are looking for cannot be determined from the reference.

  Hyperbilirubinaemia

• neonatal (transient) (see also Jaundice , fetus or newborn) P59.9|

  Enlargement, enlarged - see also Hypertrophy

• The Mapping Specialist 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 11.9. For source concepts that represent examples of poisonings caused by drugs or chemicals, the Mapping Specialist 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 1.9.

• The Mapping Specialist 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 1.3 through 1.11.

• 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 this example with reference to the term "Enlargement", the Mapping Specialist must also evaluate the alpha references for "Hypertrophy" for relevant target classifications: