Exploratory Reverse Mapping of ICD-10-CA to SNOMED CT.

This paper describes the findings of an exploratory study on reverse mapping of ICD-10-CA, the Canadian Adaptation, to SNOMED CT. For this study a set of 5,000 most frequent ICD-10-CA codes from the health ministry of a Canadian province was used. The methods included applying six mapping algorithms to each ICD-10-CA description to find the matching SNOMED CT concepts, and comparing the output against the UK SCT-ICD10 cross map for accuracy. Overall, we found successful SNOMED CT matches for ~63% of the ICD-10-CA codes. Issues requiring further attention include ways to increase successful matches and independent validation of mapping output. This study provides a glimpse of the methods that could lead to a SNOMED CT to ICD10-CA cross map. It should be of interest to those responsible for secondary use of discharge abstracts in epidemiological and statistical reporting.