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Unified Medical Language System (UMLS)

LCH_NW (Library of Congress Subject Headings) - Metathesaurus Representation


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


Skip to: Atoms, Attributes, Definitions, Relationships, Mappings

VSAB: LCH_NW_2013

Summary of Changes

LCH_NW is a new source.

Source Provided Files:

All files are available here: http://files.library.northwestern.edu/public/lcshmesh/

Additional documentation on the MARC 21 Format For Authority Data can be found here: http://www.loc.gov/marc/authority/

Documentation:


File
Description
lcsh-mesh_read.doc Description of the project and files
lchs-mesh_sample.txt Sample data

Data:


File
Description
lcsh.mrc MARC 21 format authority file, with linking data to MSH strings

Identifiers:

Identifiers are assigned as follows:

Identifier
Origin
CODE
Value of the 010 tag (Library of Congress Control Number), subfield $a
SAUI
Not Applicable
SCUI
Same as CODE
SDUI
Not Applicable

Atoms (MRCONSO):


Term Type (TTY)
Description
Origin
PT Preferred Term
CODE = Value of the 010 tag (Library of Congress Control Number)
STR = Value of 150 or 151 tag (Heading Topical Term or Geographic Name Heading); subfield delimiters are replaced with "--".
SCUI = Same as CODE
SUPPRESS = N
XM
Cross Mapping Set
This data is added during Metathesaurus source processing.

Attributes (MRSAT):

Attribute Name (ATN)
Origin
FROMRSAB
This data is added during Metathesaurus source processing.
FROMVSAB
This data is added during Metathesaurus source processing.
MAPSETRSAB
This data is added during Metathesaurus source processing.
MAPSETVERSION
This data is added during Metathesaurus source processing.
MAPSETVSAB This data is added during Metathesaurus source processing.
MTH_MAPFROMCOMPLEXITY This data is added during Metathesaurus source processing.
MTH_MAPFROMEXHAUSTIVE This data is added during Metathesaurus source processing.
MTH_MAPSETCOMPLEXITY This data is added during Metathesaurus source processing.
MTH_MAPTOCOMPLEXITY This data is added during Metathesaurus source processing.
MTH_MAPTOEXHAUSTIVE
This data is added during Metathesaurus source processing.
TORSAB
This data is added during Metathesaurus source processing.
TOVSAB
This data is added during Metathesaurus source processing.
SOS
This data is added during Metathesaurus source processing.

Definitions (MRDEF):

No definitions are included in this data.


Relationships (MRREL):

REL RELA
Inverse RELA
Origin
RQ
mapped_to/mapped_from
A subset of data found in the 750 (Topical Mappings) tag:
Where FROMEXPR and TOEXPR are simple expressions, mapping data is redundantly represented as relationships in MRREL.RRF. See the Mappings (MRMAP) section below for details.

Mappings (MRMAP):

MRMAP entries are created by processing data in the MARC 750 (Topical Mappings) tag, where:

  • 2nd indicator value of "2" is a mappng to MSH.
  • Subfield $8 is a "field link/sequence number," indicating that one LCH concept maps to two or more entities in the target source
MRMAP Field
Origin
MAPSUBSETID
Value is always "1". Used in conjunction with MAPRANK value to allow for representation when a given FROMEXPR has more than one TOEXPR value in a simple map. This data condition is found in the source where there is more than one "750" tag, and no subfield $8.
MAPRANK
Value is an integer; incremented when an LCH record has multiple "750" tags, without $8 subfields. This data condition indicates a simple one to many mapping from LCH to MSH (i.e. there is no implied "AND"). The MAPRANK field is used in conjunction with MAPSUBSETID to allow for representation when a given FROMEXPR has more than one TOEXPR value in a simple map.
FROMID
Identifier of the LCH_NW source entity being mapped from; for LCH_NW, this is always a single SCUI, with the same value as the FROMEXPR
FROMEXPR
Expression of the LCH_NW source entity being mapped from; LCH_NW, this is always a single SCUI, with the same value as the FROMEXPR
FROMTYPE
SCUI
REL
RQ (related and possibly synonymous)
RELA
mapped_to
TOID
Identifier of the MSH target entity being mapped to; this identifier is assigned during Metathesaurus source processing.
TOEXPR
The expression of the MSH target entity being mapped to, derived from "750" tag values where subfield $8 is populated, indicating a "field link/sequence number." Includes qualifier information extracted from the $x subfield, if present Note: the original data in this field is populated by MSH strings. Where possible, the strings have been translated to MSH identfiers. In a small number of cases, the string provided did not correspond to a current MSH string, and these entries were dropped during Metathesaurus source processing.
TOTYPE
Value is "SDUI" or "BOOLEAN_EXPR_SDUI" based on the absence or presence of $8 subfields.