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This document forms part of the September 2024 SNOMED CT® US Edition release distributed by the US National Library of Medicine, and is subject to the SNOMED CT® Affiliate License, details of which may be found at https://www.nlm.nih.gov/healthit/snomedct/snomed_licensing.html.

This material includes SNOMED Clinical Terms® (SNOMED CT®) which is used by permission of the International Health Terminology Standards Development Organisation (IHTSDO). All rights reserved. SNOMED CT®, was originally created by The College of American Pathologists. "SNOMED" and "SNOMED CT" are registered trademarks of International Health Terminology Standards Development Organisation, trading as SNOMED International.






Date

20200901

Document Version

1.0

Release Status

PRODUCTION RELEASE




Page At A Glance

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 SNOMED CT to ICD-10-CM map reference set is to support semi-automated generation of ICD-10-CM codes from clinical data encoded in SNOMED CT for reimbursement and statistical purposes.

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).  

1.1 Background

This document provides a summarized description of the content changes for the NLM maintained SNOMED CT to ICD-10-CM mapping reference set found in the September 2020 release of the SNOMED CT® US Edition. These release notes also include technical notes detailing the known issues which have been identified. These are content or technical issues where the root cause is understood, and the fix has been discussed and agreed, but has yet to be implemented.

This document is available as a web resource as well as alongside the September 2020 US Edition release (https://www.nlm.nih.gov/healthit/snomedct/us_edition.html). 

The mapping methodology follows closely that of the SNOMED CT to ICD-10 Crossmap Project, a collaborative project between SNOMED International and the World Health Organization. Dual independent mapping by trained terminology specialists is employed to assure quality and reduce variability. Identical maps created independently are accepted as final, while discordant maps are reviewed by a third expert. Regular team meetings are held to discuss problematic and ambiguous cases.

1.2 Scope

This document covers the characteristics of this release of the map, including concept counts and file format. For details about how the map is created please refer to the technical specifications for SNOMED CT to ICD-10-CM map (SNOMED CT Managed Service - US Edition Mapping SNOMED CT to ICD-10-CM Technical Specifications - September 2020). The Map corresponds to the September 2020 release of the US Edition of SNOMED CT (https://www.nlm.nih.gov/healthit/snomedct/us_edition.html) and the 2021 version of ICD-10-CM.

1.3 Purpose of the Map

  • To provide a semi-automated coding of ICD-10-CM statistical classification data from a clinical record which is clinically encoded in SNOMED CT

  • For development of ICD-10-CM classification codes from SNOMED CT encoded records for use in registries and diagnosis groupers

  • Please note - this Map is NOT a completely automated ICD-10-CM coding from a SNOMED CT source. 

1.4 Audience

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 Summary

This September 2020 SNOMED CT US Edition (20200901) publication of the the SNOMED CT to ICD-10-CM map marks the fifth release with the mapping tooling and map release production provided by SNOMED International Managed Service. Quality assurance of the release was completed by both NLM and SNOMED International. 

2.2  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 finding|, 272379006 |event| and 243796009 |situation with explicit context|.

2.2.1 March 2020 SNOMED CT to ICD-10-CM refset statistics

Total number of SNOMED CT source concepts

126,553

Source concepts could not be assigned a map target due to issues of ambiguity or target scope

10,622

This map release includes a total of 214,313 map records, with a maximum of 28 map records per map group. 

2.3  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 a SNOMED International 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.

This publication of the MAP employs a Descriptor refset, an Extended Map refset and a Module Dependency refset as documented in that publication. 

2.4 RF2 refsets in this publication 

The SNOMED CT to ICD-10-CM map is released in RF2 format within the SNOMED CT US Edition (https://www.nlm.nih.gov/healthit/snomedct/us_edition.html). The map is also available in a human readable format (tls_Icd10cmHumanReadableMap_US1000124_20200901.tsv) contained within the documentation folder on the US Edition Release page.

The SNOMED CT to ICD-10-CM map is released as Refsetid 6011000124106 | ICD-10-CM extended map reference set (foundation metadata concept)|.

The SNOMED CT to ICD-10-CM map refset data are contained in three separate files: 

  • Extended Map: contains the core of the Map data. There are one or more map records for each source concept mapped, including the ICD-10-CM target codes. Found in the Map folder under Refset in the Full, Snapshot, and Delta Release Type folders: xder2_iisssccRefset_ExtendedMap[Full-Snapshot-Delta]_US1000124_20200901.txt. 

  • 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

2.5 Additional Resources

Additional resources have been provided to support the use of the Map. 

Please note - March 2019 marked the last time the documentation folder was included in the SNOMED CT US Edition release.  Instead the Release Notes are now available as a PDF download alongside the US Edition Release Notes on the NLM downloads page as well as an online resource.

2.5.1 Browsable Spreadsheet

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 on the US Edition downloads page. 

2.5.2 Technical Documentation 

Technical documentation which summarizes the rationale, procedures, technical artifacts and project overview is included with the publication as the pdf file: SNOMED CT Managed Service - US Edition Mapping SNOMED CT to ICD-10-CM Technical Specifications - September 2020. Accompanying the technical documentation is a collection of sample maps available as Appendix_icd_10_cm_exemplar_20200901.xlsx.

2.5.3 iMagic Mapper

The I-MAGIC (Interactive Map-Assisted Generation of ICD Codes - https://imagic.nlm.nih.gov/imagic/code/map) Algorithm utilizes the SNOMED CT to ICD-10-CM Map in a real-time, interactive manner to generate ICD-10-CM codes. This demo tool simulates the Problem List of an EHR to illustrate how the healthcare provider can capture clinical problems in SNOMED CT and then derive ICD-10-CM codes for reimbursement and other purposes.

3 Technical Notes

3.1 Summary

This section of the document provides a summary of known technical issues and current changes. Please see the Technical Specifications Documentation for additional information. 

3.2 Known Issues

Known Issues are content or technical issues where the root cause is understood, and the resolution has been discussed and agreed but has yet to be implemented.  This can be due to a number of reasons, from lack of capacity within the current map editing cycle, to the risk of impact to the stability of the Map if the fix were to be deployed at that stage in the Product lifecycle.

For the SNOMED CT to ICD-10-CM map, there is no Known Issues identified.


3.3 Technical Updates

No ICD-10-CM technical updates in this release.

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 Feedback and suggestions

We welcome questions, comments or suggestions to improve the quality, accuracy and usability of the SNOMED CT US Edition. Please send feedback to NLM Customer Support https://support.nlm.nih.gov.

6 Appendix: File format specifications

6.1 Refset Descriptor refset (der2_cciRefSet_DescriptorSnapshot_INT_20200901)

(der2 designates a data file of format RF2; cci denotes a Concept-Concept-Integer refset; INT identifies the international version; 20200901 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

Set to a descendant of 900000000000457003  |Reference set attribute| in the metadata hierarchy, that describes the additional attribute extending the reference set.

attributeType

SctId

A descendant of 900000000000459000 |Attribute type| in the metadata hierarchy, that describes the type of the additional attribute extending the reference set.

attributeOrder

Integer

An unsigned integer, providing an ordering for the additional attributes extending the reference set. A zero value here is used for the row that describes the referenced component within the reference set. One additional active row exists for each attribute extending the reference set.


6.2 Module Dependency refset (der2_ssRefSet_ModuleDependencySnapshot_INT_20200901)

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 (der2_iissscRefset_ExtendedMapSnapshot INT_20200901)

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_20200901)

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

correlationId

SctId

A child of |Map correlation value| in the metadata hierarchy, identifying the correlation between the SNOMED CT concept and the target code.

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


Patrick McLaughlinApproved




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

9.020180301Susan Roy, Kin Wah FungRelease notes for 20180301 version of the map
10.020180807Susan Roy, Kin Wah FungRelease notes for 20180901 version of the map
11.020190728Julia XuRelease notes for 20190901 version of the map
12.020200214Julia XuRelease notes for 20200301 version of the map
13.020200814Julia XuRelease notes for 20200901 version of the map


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