NLM logo

Unified Medical Language System (UMLS)

UMLS Vocabularies

SNOMEDCT_US (SNOMED CT, US Edition) - Metathesaurus Representation


This page lists UMLS Metathesaurus data elements and traces them back to the specific source data that populates them.

VSAB: SNOMEDCT_2021_03_01
Version: 20210301
ReleaseCode: US1000124
Edition: USEditionRF2


Summary of Changes

There have been no changes to the SNOMEDCT format or processing of the data.


Original Files:

The Metathesaurus SNOMEDCT data is taken from the following tab-delimited SNOMEDCT files, found in the specified folders under SnomedCT_<edition>_PRODUCTION_<YYYYMMDD>T120000Z/Snapshot/:

Subfolder File name Short name
Terminology sct2_Concept_Snapshot_<ReleaseCode>_<YYYYMMDD>.txt Concept
Terminology sct2_Description_Snapshot-en_<ReleaseCode>_<YYYYMMDD>.txt Description
Terminology sct2_Relationship_Snapshot_<ReleaseCode>_<YYYYMMDD>.txt Relationship
Terminology sct2_TextDefinition_Snapshot_<ReleaseCode>_<YYYYMMDD>.txt Definition
Refset/Content der2_cRefset_AssociationSnapshot_<ReleaseCode>_<YYYYMMDD>.txt Association
Refset/Content der2_cRefset_AttributeValueSnapshot_<ReleaseCode>_<YYYYMMDD>.txt AttributeValue
Refset/Content der2_Refset_SimpleSnapshot_<ReleaseCode>_<YYYYMMDD>.txt Simple
Refset/Language der2_cRefset_LanguageSnapshot-en_<ReleaseCode>_<YYYYMMDD>.txt Language
Refset/Map der2_iisssccRefset_ExtendedMapSnapshot_<ReleaseCode>_<YYYYMMDD>.txt ExtendedMap
Refset/Map der2_sRefset_SimpleMapSnapshot_<ReleaseCode>_<YYYYMMDD>.txt SimpleMap
Refset/Metadata der2_ciRefset_DescriptionTypeSnapshot_<ReleaseCode>_<YYYYMMDD>.txt DescriptionType
Refset/Metadata der2_ssRefset_ModuleDependencySnapshot_<ReleaseCode>_<YYYYMMDD>.txt ModuleDependency
Refset/Metadata der2_cciRefset_RefsetDescriptorSnapshot_<ReleaseCode>_<YYYYMMDD>.txt RefsetDescriptor
Identifiers are assigned as follows:
  • CODE: Description.conceptId
  • SAUI: Description.id
  • SCUI: Same as CODE
  • SDUI: Not Applicable

Atoms (MRCONSO)

For readability, selected field values are mapped as follows in this documentation:

File.field Value Description
Description.typeId 900000000000003001 Fully specified name (FSN)
Description.typeId 900000000000013009 Synonym
Description/Concept/Language.active 1 Active
Description/Concept/Language.active 0 Inactive
Language.refSetId 900000000000509007 US English
Language.refSetId 900000000000508004 Great Britain English (GB)
Language.acceptabilityId 900000000000548007 Preferred
Language.acceptabilityId 900000000000549004 Acceptable
Description/Concept.ModuleId 900000000000207008 SNOMEDCT Core
Term Type Origin
FN Full form of descriptor

Description..typeId = FSN
Description.active = Active
Concept.active = Active

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=N
OF Obsolete fully specified name

Description.typeId = FSN
Description.active = Inactive

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=O
OAF Obsolete active fully specified name
Description.typeId = FSN
Description.active = Active
Concept.active = Inactive

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE = O
PT Designated preferred name

Description.typeId = Synonym
Description.active = Active
Concept.active= Active
Language.refSetId = US English Language reference set (Active)
Language.acceptabilityId = Preferred

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=N
PTGB British Preferred Term

Description.typeId = Synonym
Description.active = Active
Concept.active = Active
Language.refSetId = GB (not Active in US refSet)
Language.acceptablityId = Preferred

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=N
OP Obsolete preferred name

Description.typeId = Synonym
Description.active = Inactive
Language.acceptabilityId = Preferred

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=O
OAP Obsolete active preferred term

Description.typeId = Synonym
Description.active = Active
Concept.active = Inactive
Language.acceptabilityId: Preferred (not Acceptable in US refset)

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE = O
SY Synonym

Description.typeId = Synonym
Description.active = Active
Concept.active= Active
Language.refSetId = US English Language reference set (Active)
Language.acceptabilityId = Acceptable

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=N
SYGB British Synonym

Description.typeId = Synonym
Description.active = Active
Concept.active = Active
Language.refSetId = GB (not Active in US refSet)
Language.acceptablityId = Acceptable

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=N
IS Obsolete Synonym

Description.typeId = Synonym
Description.active = Inactive
Language.acceptabilityId = Not Preferred in any refset

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE=O
OAS Obsolete active synonym

Description.typeId = Synonym
Description.active = Active
Concept.active = Inactive
Language.acceptabilityId = Acceptable (not Preferred in US Refset)

CODE, SCUI = Description.conceptId
SAUI = Description.id
STR = Description.term
SUPPRESSIBLE = O
MTH_FN
MTH_OF
MTH_OAF
MTH_PT
MTH_PTGB
MTH_OP
MTH_OAP
MTH_SY
MTH_SYGB
MTH_IS
MTH_OAS
Special MTH_* forms are algorithmically generated for atoms with the termtypes listed above as follows:

If the STR contains the markup syntax SNOMEDCT uses to indicate superscripts ("^sup^") and/or subscripts (">sub<"), two MTH_* forms are generated:
1. One in which the markup syntax is removed, e.g., "CO>2<" becomes "CO2"
2. One in which the markup syntax is converted to an xml-style syntax using "<sup> for superscripts and "<sub>" for subscripts, e.g., "CO>2<" becomes "CO<sub>2</sub>".

This data is added during Metathesaurus source processing
SB Subset

For any conceptId that occurs as a refsetId in any refSet, its PT is duplicated as an SB atom.

CODE, SCUI = refsetId
SAUI = Not populated
STR = Description.term
SUPPRESSIBLE = N
XM Cross Mapping Set
One XM (cross Mapping set) atom is generated for each refsetId in ExtendedMap as follows:

CODE, SCUI = refsetId
SAUI = Not populated
STR = "SNOMEDCT_US_yyyy_mm_dd to <VSAB> Mappings"
SUPPRESSIBLE = N

Attributes (MRSAT)

Attribute Name STYPE Origin
ACTIVE SCUI Concept.active
also affects the TTY values of this concept's descriptions
CASE_SIGNIFICANCE_ID AUI Description.caseSignificanceId

900000000000017005 - Entire term case sensitive
900000000000020002 - Initial character case insensitive
900000000000448009 - Case insensitive
CHARACTERISTIC_TYPE_ID RUI Relationship.characteristicTypeId
CTV3ID SCUI SimpleMap.mapTarget where refSetId = 900000000000497000 (CTV3 simple map)
DEFAULT_LANGUAGECODE SCUI The 2-character ISO639-1 code indicating the language of the source (attached to the SCUI of the source root)
DEFAULT_MODULE_ID SCUI Core Module Identifier (attached to the SCUI of the source root)
DEFINITION_STATUS_ID SCUI Concept.definitionStatusId - indicates whether this concept is primitive or fully defined
DESCRIPTION_FORMAT SCUI DescriptionType.descriptionFormat
DESCRIPTION_LENGTH SCUI DescriptionType.descriptionLength
EFFECTIVE_TIME SCUI Concept.effectiveTime
FROMRSAB AUI SNOMEDCT_US, attached to the XM atom for the Cross Map Set
FROMVSAB AUI "SNOMEDCT_US_yyyy_mm_dd", attached to the XM atom for the Cross Map Set
ICD-O-3_CODE SCUI SimpleMap.mapTarget where refSetId = 446608001 (ICD-O simple map reference set)
INACTIVATION_INDICATOR AUI AttributeValue.valueId where refSetId = 900000000000489007 (Description inactivation indicator reference set)
INACTIVATION_INDICATOR SCUI AttributeValue.valueId where refSetId = 900000000000490003 (Concept inactivation indicator reference set)
MAPSETNAME AUI A MAPSETNAME attribute is created for each unique value of refsetId ExtendedMap, attached to the XM atom for the Cross Map Set. The ATV value is the STR of the relevant SB atom.
MAPSETRSAB AUI "SNOMEDCT_US", attached to the XM atom for the Cross Map Set
MAPSETSID AUI A MAPSETSID attribute is created for each unique value of ExtendedMap.refSetId, attached to the XM atom for the Cross Map Set
MAPSETVERSION AUI Version, attached to the XM atom for the Cross Map Set
MAPSETVSAB AUI "SNOMEDCT_yyyy_mm_dd", attached to the XM atom for the Cross Map Set
MODIFIER_ID RUI Relationship.modifierId; always 900000000000973015 (Existential)
MODULE_ID AUI Description.moduleId; only included when moduleId is not the default (core) module
MODULE_ID RUI Relationship.moduleId; only included when moduleId is not the default (core) module
MODULE_ID SCUI Concept.moduleId; only included when moduleId is not the default (core) module
MTH_MAPFROMCOMPLEXITY AUI "SINGLE_SCUI", attached to the XM atom for the Cross Map Set; this data is added during Metathesaurus Source processing.
MTH_MAPFROMEXHAUSTIVE AUI "N", attached to the XM atom for the Cross Map Set; this data is added during Metathesaurus Source processing
MTH_MAPSETCOMPLEXITY AUI "N TO N", attached to the XM atom for the Cross Map Set; this data is added during Metathesaurus Source processing
MTH_MAPTOCOMPLEXITY AUI "SINGLE SDUI, MULTIPLE SDUI", attached to the XM atom for the Cross Map Set; this data is added during Metathesaurus Source processing
MTH_MAPTOEXHAUSTIVE AUI "N", attached to the XM atom for the Cross Map Set; this data is added during Metathesaurus Source processing
REFSET_PATTERN SCUI A name for the type (corresponding to the collection of included fields) of the referenced RefSet; attached to the SCUI of RefsetDescriptor.moduleId
SOS AUI Describes the Cross Map set; attached to the AUI of the XM atom
SOURCE_EFFECTIVE_TIME RUI ModuleDependency.sourceEffectiveTime
SUBSET_MEMBER AUI Attached to each member (referencedComponentId) of each RefSet, this attribute includes the refsetId optionally followed by a "~" character, a refSet membership-attribute name, another "~", and a the value of the refset membership-attribute
SUBSET_MEMBER SCUI Attached to each member (referencedComponentId) of each RefSet, this attribute includes the refsetId optionally followed by a "~" character, a refSet membership-attribute name, another "~", and a the value of the refset membership-attribute
TARGET_EFFECTIVE_TIME RUI ModuleDependency.targetEffectiveTime
TORSAB AUI The RSAB corresponding to the target source of the cross map set, per release notes
TOVSAB AUI The VSAB of the target source, per release notes
TYPE_ID AUI Description.typeId
UMLSREL SCUI The REL for MRREL.RRF, attached to the concept for each typeId value used in the Relation file.
UMLSRELA SCUI The RELA value used in MRREL.RRF, attached to the concept for each typeId value used in the Relation file.

Definitions (MRDEF)

Field Origin
SATUI Definition.id
DEF Definition.term
SUPPRESS Definition.active (N for active = 1; O for active = 0)

Relationships (MRREL)

REL/Inverse REL RELA/Inverse RELA ORIGIN
CHD/PAR isa/inverse_isa Hierarchical relationships are derived from rows of relationships where type.Id = 116680003 ("Is a")
RB/RN
RO
SY
(many RELA values) Derived from rows of relationships where typeId is not 116680003 ("Is a")
REL and RELA values used for each typeId are specified by UMLSREL and UMLSRELA attributes, respectively (see above).
RQ mapped_from, mapped_to Represent the 1 - 1 cross maps in ExtendedMaps

Mappings (MRMAP)

The Metathesaurus includes SNOMEDCT_US mappings (an XM atom, along with associated attributes and mappings) to ICD10 and ICD10CM. These are extracted from ExtendedMap.