Mapping SNOMED CT to ICD-10-CM
Creators: name: Xu, Junchuan
Publisher: name: No Publisher Supplied
Year: 2016

description: A SNOMED CT-encoded problem list is required to satisfy the Certification Criteria for Stage 2 “Meaningful Use”. ICD-10-CM has replaced ICD-9-CM as the reimbursement code set in 2015. Having a cross-map from SNOMED CT to ICD-10-CM would promote the use of SNOMED CT as the primary problem list terminology, while easing the transition to ICD-10-CM. There is no established principle and methodology on systematically and semantically linking SNOMED CT to ICD-10-CM.          This research project describes the development of mapping principle, mapping guidelines, mapping tools and mapping methodology for a rule-based crosswalk to support semi-automatic generation of ICD-10-CM codes from SNOMED CT-encoded data. A series of mapping guidelines were developed based on the clinical use case, SNOMED CT modeling convention, and ICD-10-CM classification guidelines. One of the important methodology in developing the map set is using triangulation in generating legacy maps. Using the SNOMED CT to ICD-9-CM map and General Equivalence Mappings sequentially, Indirect Map was generated from SNOMED CT to ICD-10-CM for 96.2% of the SNOMED CT concepts within the scope of the study. Another innovation in this crossmapping research is implementation of a principle to handle age specification. The age rule was one type of rule to handle cases in which one SNOMED CT concept can map to different ICD-10-CM codes depending on the age of the patient. The age rule quality assurance (QA) was a mechanism to capture the age specification that can be easily missed by manual mapping.          The results showed that the mapping guidelines ensured the mapping consistency, which potentially would reduce the mapping discrepancy between the two independent parallel mapping efforts. It also made it possible that the map set can be used in a meaningful way when data is exchanged. On this triangulation method in generating legacy map, an Indirect Map generated from SNOMED CT to ICD-10-CM covered a very high percentage of SNOMED CT concepts. Overall, this Indirect Map had a moderate degree of agreement with the Direct SNOMED CT to ICD-10-CM map. However, the indirect synonymy maps have much higher precision and can be used for quality assurance (QA) of the three maps. The age rule QA identified 342 out of 7,277 concepts which potentially required age rules, among these 50.3% turned out to be true positives. Without this QA, a large proportion of age rules in the published Map would have been missed.          The outcomes of this research project include a set of mapping principle, mapping guidelines, mapping tools and mapping methodology for a rule-based crosswalk from SNOMED CT to ICD-10-CM. All these could be used as a prototype in other cross standard mappings. For example, in the US, ICD-10-PCS officially replaced ICD-9-CM from October 2015 onwards. A project was formulating earlier this year (2015) for the purpose of creating the map from SNOMED CT procedure to ICD-10-PCS. It is a pleasant finding that tooling, principles and guidelines established in SNOMED CT to ICD-10-CM mapping can be re-used, with modifications, for the PCS mapping process.