1 Introduction
SNOMED CT terminology provides a common language that enables a consistent way of indexing, storing, retrieving, and aggregating clinical data across specialties and sites of care. The SNOMED CT US Edition is a combination of the full SNOMED CT International Edition and the US Extension of SNOMED CT. The US Edition eliminates the need for implementers to manually combine the US Extension and International releases.
The International Health Terminology Standards Development Organisation (IHTSDO®), trading as SNOMED International, maintains the SNOMED CT technical design, the content architecture, the SNOMED CT content (includes the concepts table, the descriptions table, the relationships table, a history table, and ICD mappings), and related technical documentation. SNOMED CT US Edition is developed and maintained by the United States National Library of Medicine and is available to authorized Unified Medical Language System (UMLS) Metathesaurus Licensees. This material includes SNOMED CT which is used by permission of the IHTSDO. All rights reserved.
SNOMED CT was originally created by the College of American Pathologists. "SNOMED" and "SNOMED CT" are registered trademarks of IHTSDO. You must have a UMLS Metathesaurus license to access SNOMED CT US Edition data files. License information is available from NLM (https://www.nlm.nih.gov/healthit/snomedct/snomed_licensing.html).
1.2 Purpose
This is an update of the SNOMED CT to ICD-10-CM Cross Map (herein referred to as ‘the MAP’). The MAP corresponds to the March 2018 release of the US Edition of SNOMED CT and the 2018 version of ICD-10-CM.
1.3 Audience for this document
All parties who wish to understand the MAP and/or to employ it for semi-automatic translation between SNOMED CT and ICD-10-CM should read this document. This may include vendors of electronic health records, terminology developers and managers.
2 Cross map content overview
2.1 Scope of publication
The MAP is a directed set of relationships from SNOMED CT source concepts to ICD-10-CM target classification codes. The SNOMED CT source domains for the MAP are limited to subtypes of 404684003 |clinical findings|, 272379006 |event| and 243796009 |situation with explicit context|.
This update of the MAP includes:
- 119,270 SNOMED CT source concepts including:
- 110,812 clinical findings
- 3,637 events
- 4,821 situations with explicit context
- 10,241 source concepts could not be assigned a map target due to issues of ambiguity or target scope
- A total of 200,544 map records, with a maximum of 23 map records per map group
The SNOMED CT to ICD-10-CM mapping files can be downloaded as a standalone file (http://www.nlm.nih.gov/research/umls/mapping_projects/snomedct_to_icd10cm.html). The files are contained in the RF2 folder:
The Human Readable Map – Documentation folder
Refset Descriptor Snapshot – Snapshot à Refset à Metadata
Extended Map Snapshot – Snapshot à Refset à Map
Module Dependency Snapshot – Snapshot à Refset à Metadata
2.2 What is a refset?
A Reference Set (refset) is a set of references to SNOMED CT components which may associate additional properties with members of the set. It may also indicate associations between members of the set or between members of the set and content of another nomenclature, classification or knowledge structure. The uses of Reference sets include identification of subsets of SNOMED CT content, representation of alternative hierarchical structures and cross maps to classifications. References Sets are a part of SNOMED CT Release Format 2 that provides a general purpose extensibility mechanism. Refsets are an IHTSDO standard artifact that complies with the technical specifications documented in the document SNOMED CT Release Format 2.0 Reference Set Specifications, accessible on line as part of the Technical Implementation Guide. (http://doc.ihtsdo.org/download/doc_TechnicalImplementationGuide_Current-en-US_INT_20150131.pdf).
This publication of the MAP employs a Descriptor refset, an Extended Map refset and a Module Dependency refset as documented in that publication.
2.3 RF2 refsets in this publication
The ICD-10-CM MAP is contained in three separate files. The MAP is identified by the refsetid 6011000124106.
- Refset Descriptor: contains metadata from the SNOMED CT metadata hierarchy (children of 9000000000000454005 |foundation metadata concept|) which describes the attributes of the publication refsets and their information content
- Module Dependency: designates the versions of other SNOMED CT modules upon which this publication of the MAP depends
Extended Map: contains the core publication of MAP data. There are one or more map records for each source concept mapped, including the ICD-10-CM target codes.
2.4 Spreadsheet dataset for browsing
To support browsing and understandability of the MAP, a tab delimited UTF-8 dataset which can be imported into spreadsheet software such as Microsoft Excel® is included with the release. This can be loaded with the text import features of Excel and most spreadsheets. The spreadsheet data format mimics the exemplar appendices of the technical documentation and is a “readable” version of the map that can be understood by a non-technical individual. This file is not in RF2 format and can be found in the Documentation directory.
2.5 Technical documentation
Technical documentation which summarizes the rationale, procedures, technical artifacts and project overview is included with the publication as the pdf file: Mapping SNOMED CT to ICD-10-CM 201603. Accompanying the technical documentation is a collection of sample maps available as Appendix_icd_10_cm_exemplar_20160603.xlsx.
3 Publication history
Publication effective date | Version | Overview and purpose |
2/29/2012 | 0.01 | Preview publication of Phase 1 mapping data fit for publication 2/21/2012
|
7/6/2012 | 1.0 | Final publication of the Phase 1 MAP
|
6/1/2013 | 2.0 | Updated and expanded version of the MAP
|
12/20/2013 | 3.0 | Updated and expanded version of the MAP
|
9/1/2014 | 4.0 | Updated and expanded version of the MAP. This is the first release that is also published in the US Edition of SNOMED CT.
|
9/1/2015 | 5.0 | Updated and expanded version of the MAP
|
3/1/2016 | 6.0 | Updated and expanded version of the MAP
|
10/1/2016 | 6.1 | MAP synchronized with September 2016 release of US Edition of SNOMED CT
|
2/1/2016 | 7.0 | Updated and expanded version of the MAP
|
4 Quality assurance and maintenance
Mapping procedures as outlined in the technical documentation consist of dual independent mapping of all source concepts with map records sent to publication only after consensus of the independent mappers is reached. The MAP will be periodically updated with new versions of SNOMED CT and ICD-10-CM. Future expansion of coverage of SNOMED CT concepts will depend on user feedback and availability of resources.
5 Queries and comments
Please send comments and questions about the MAP to Dr. Kin Wah Fung of the Lister Hill National Center for Biomedical Communications, National Library of Medicine.
6 Appendix: File format specifications
6.1 Refset Descriptor refset (xder2_cciRefSet_DescriptorSnapshot_INT_yyyymmdd)
(der2 designates a data file of format RF2; cci denotes a Concept-Concept-Integer refset; INT identifies the international version; yyyymmdd is the year, month and date of publication)
Field | Data type | Purpose | |
id | UUID | A 128 bit unsigned integer, uniquely identifying the map category record | |
effectiveTime | Time | Specifies the inclusive date at which this change becomes effective. | |
active | Boolean | Specifies whether the member’s state was active (=1) or inactive (=0) from the nominal release date specified by the effectiveTime field. | |
moduleId | SctId | Identifies the member version’s module. Set to a child of 900000000000443000|Module| within the metadata hierarchy. | |
refSetId | SctId | Indicates that this is part of a "reference set descriptor"; concept Id 900000000000456007 | Reference set descriptor reference set (foundation metadata concept)| | |
referencedComponentId | SctId | The SCT identification of the refset which is described; a metadata descendant of 9000000000000455006 |Reference Set| | |
attributeDescription | SctId |
| |
attributeType | SctId |
| |
attributeOrder | Integer |
|
6.2 Module Dependency refset (xder2_ssRefSet_ModuleDependencySnapshot_INT_yyyymmdd)
Field | Data type | Purpose |
id | UUID | A 128 bit unsigned integer, uniquely identifying the map category record |
effectiveTime | Time | Specifies the inclusive date at which this change becomes effective. |
active | Boolean | Specifies whether the member’s state was active (=1) or inactive (=0) from the nominal release date specified by the effectiveTime field. |
moduleId | SctId | Identifies the member version’s module. Set to a child of 900000000000443000|Module| within the metadata hierarchy. |
refSetId | SctId | Set to one of the children of the 447250001 |Complex map type| concept in the metadata hierarchy. |
referencedComponentId | SctId | A reference to the module on which this module depends, a descendant of 900000000000443000|Module| in the metadata hierarchy. |
sourceEffectiveTime | String | The effective time of the source module. This allows a specific module version to be selected as having a dependency. The effectiveTime must match exactly. |
targetEffectiveTime | String | The effective time of the target module. This allows a specific module version to be selected as being the subject of a dependency. The effectiveTime must match exactly. |
6.3 Extended Map refset (xder2_iissscRefset_ExtendedMapSnapshot INT_yyyymmdd)
Field | Data type | Purpose |
id | UUID | A 128 bit unsigned integer, uniquely identifying the map record |
effectiveTime | Time | Specifies the inclusive date at which this change becomes effective. |
active | Boolean | Specifies whether the member’s state was active (=1) or inactive (=0) from the nominal release date specified by the effectiveTime field. |
moduleId | SctId | Identifies the member version’s module. Set to a child of 900000000000443000|Module| within the metadata hierarchy. |
refSetId | SctId | Set to one of the children of the |Complex map type| concept in the metadata hierarchy. |
referencedComponentId | SctId | The SNOMED CT source concept ID that is the subject of the map record. |
mapGroup | Integer | An integer identifying a grouping of complex map records which will designate one map target at the time of map rule evaluation. Source concepts that require two map targets for classification will have two sets of map groups. |
mapPriority | Integer | Within a map group, the mapPriority specifies the order in which complex map records should be evaluated to determine the correct map target. |
mapRule | String | A machine-readable rule, (evaluating to either ‘true’ or ‘false’ at run-time) that indicates whether this map record should be selected within its map group |
mapAdvice | String | Human-readable advice that may be employed by the software vendor to give an end-user advice on selection of the appropriate target code. This includes a) a summary statement of the map rule logic, b) a statement of any limitations of the map record and c) additional classification guidance for the coding professional. |
mapTarget | String | The target ICD-10 classification code of the map record. |
correlationId | SctId | A child of |Map correlation value| in the metadata hierarchy, identifying the correlation between the SNOMED CT concept and the target code. |
mapCategoryId | SctId | Identifies the SNOMED CT concept in the metadata hierarchy which is the MapCategory for the associated map record. This is a subtype of 447634004 |ICD-10 Map Category value|. |
6.4 Map browser spreadsheet (tls_ICD10HumanReadableMap_INT_yyyymmdd)
The browser spreadsheet dataset is the same as the Extended Map Refset with the descriptive names for the SNOMED CT concept, ICD-10-CM code and mapCategoryId added for readability.
Field | Data type | Purpose |
id | UUID | A 128 bit unsigned integer, uniquely identifying the map category record |
effectiveTime | Time | Specifies the inclusive date at which this change becomes effective. |
active | Boolean | Specifies whether the member’s state was active (=1) or inactive (=0) from the nominal release date specified by the effectiveTime field. |
moduleId | SctId | Identifies the member version’s module. Set to a child of 900000000000443000|Module| within the metadata hierarchy. |
refSetId | SctId | Set to one of the children of the |Complex map type| concept in the metadata hierarchy. |
referencedComponentId | SctId | The SNOMED CT identifier of the source concept that is being mapped in this record |
sctName | String | The fully specified name of the SNOMED CT source concept being mapped |
mapGroup | Integer | A collation identifier which specifies one or more map records which are to be evaluated in sequence for determination of at most one ICD-10 target codes for this map |
mapPriority | integer | The sequence number for evaluation of this map record within the map group |
mapRule | string | The map rule for this map record |
mapAdvice | string | The map advice for this map record |
mapTarget | string | Target ICD-10 classification code for this map record |
icdName | string | WHO term assigned to the target ICD-10 code for this record |
mapCategoryValueId | SctId | The metadata identifier for the map category assigned to this map record, a child of 447634004 |ICD-10 map category value| |
mapCategoryValue | string | Primary term for the map category metadata assigned to this map record |
Approvals
Final Version | Date | Approver | Comments |
---|---|---|---|
1.0 | Terance Shird | ||
1.0 |
| Rory Davidson | |
1.0 | Kin Wah | ||
1.0 | Suzy Roy |
Draft Amendment History
Version | Date | Editor | Comments |
---|---|---|---|
1.0 | 20120703 | Kin Wah Fung | Final release notes of Phase 1 map |
2.0 | 20130601 | Kin Wah Fung | Release notes of updated map |
3.0 | 20131220 | Kin Wah Fung | Release notes of updated map |
4.0 | 20140901 | Kin Wah Fung | Release notes of updated map |
4.1 | 20150225 | Susan Roy, Kin Wah Fung | Release notes for 2015 March US Edition |
5.0 | 20150630 | Kin Wah Fung | Release notes for 20150901 version of the map |
5.1 | 20150901 | Kin Wah Fung, Susan Roy | Release notes for 2015 September US Edition |
6.0 | 20160624 | Kin Wah Fung | Release notes for 201603 version of the map |
6.1 | 20161006 | Kin Wah Fung | Release notes for 201609 version of the map |
7.0 | 201702 | Kin Wah Fung Susan Roy | Release notes for 201702 version of the map |
7.1 | 201703 | Kin Wah Fung | Release notes for 201703 version of the map |
8.0 | 201709 | Kin Wah Fung | Release notes for 201709 version of the map |