Use of MeSH in Cataloging
The Cataloging and Metadata Management Section (CaMMS) at NLM uses Medical Subject Headings (MeSH) for assigning subject headings to materials in all formats. With few exceptions, catalogers apply the same basic principles as those used by indexers in assigning MeSH terms for the subject analysis of bibliographic materials (cf. Use of MeSH in Indexing). The information below outlines the exceptions between the use of MeSH as applied by catalogers versus indexers.
Catalogers use the MARC21 6XX fields in the bibliographic record for recording subject access entries . All MARC 6XX fields have a second indicator “2” to show that they come from the MeSH thesaurus.
- MeSH topical descriptors are recorded in MARC 650 ‡a; primary subject headings are coded with a MARC 650 first indicator of “1”, secondary subjects are assigned the first indicator of “2.” MeSH topical descriptors can be identified in the MeSH Browser by the fact that unique ID begins with the letter "D."
- Qualifiers are recorded in MARC 650 ‡x. MeSH qualifiers can be identified in the MeSH Browser by the fact that the unique ID begins with the letter “Q” and the terms are all in lower case.
- MeSH geographical descriptors are recorded in MARC 651 ‡a with the first indicator blank, and second indicator of 2. These are a type of topical descriptor located in the Z tree.
- Publication characteristics are recorded in the MARC 655 field with the first indicator blank, and second indicator of 2. These are a type of topical descriptor located in the V tree.
Number of Subject Headings Assigned
In general, catalogers only assign MeSH headings for concepts that cover at least 20% of the work being cataloged. The maximum number of subjects assigned rarely exceeds 6-7 terms. For example, in a book of 35 chapters, catalogers do not assign terms that only apply to a single chapter.
Supplementary Concept Records (SCR)
Supplementary Concept Records are created for some chemicals, drugs, and other concepts such as rare diseases. Catalogers are not permitted to use these terms and instead should use the descriptor(s) listed under “Heading Mapped to” field. SCRs can be identified in the browser by the fact that the unique ID begins with the letter “C.”
The Annotation field of the MeSH Browser record provides more guidance for consistent application of MeSH. Annotations applicable specifically to cataloging are prefaced by the word "CATALOGER."
- Annotation: CATALOGER: Do not use
Catalogers may not use these headings. For example, Diet, Food, and Nutrition
The annotations below reflect NLM practice. Other libraries are not obligated to follow these annotations.
- Annotation: CATALOGER: Use for historical material only
NLM catalogers use for works housed in the History of Medicine Division (HMD) only. For example, Letter
- Annotation: CATALOGER: Used by collaborating partners only
Used only by NLM collaborating partners (i.e., outside institutions who have created cataloging records for NLM). For example, Unpublished Works
Check tags are used by indexers on all articles to which they apply, to identify categories of research subjects, type of research, or other specific parameters of the subject content of an article. They are annotated "NIM as check tag." Catalogers may use these as regular MeSH descriptors when they are the focal point of an item cataloged. Catalogers may not use the two check tags, Male and Female.
Names or Work Titles as Subjects
Catalogers assign subjects as appropriate for any personal or corporate names or work titles discussed in the item being cataloged. The headings assigned are taken from the National Authority File (NAF), not from MeSH, and are created according to current cataloging rules and practices. These types of headings are annotated "CATALOGER: Use NAF entry." The subjects are recorded in MARC 600, 610, 611, or 630 fields, not in the 650 field. NLM does not use qualifiers with personal or corporate names or work title subject headings. Generally, personal or corporate names used as subjects are coordinated with the appropriate MeSH descriptor for the type of corporate entity, named group, or specialty if applicable.
Catalogers may use MeSH with the annotation “CATALOGER: Coordinate with specific NAF entry if applicable” in addition to the specific NAF entry when appropriate, e.g., Visible Human Projects.
Discontinuance of Subject Strings in Record Distribution
Prior to December 2015, NLM provided a specially programmed output with a traditional subject string of 650 ‡a ‡x ‡z ‡v for subscribers of CATFILE and SERFILE. As of December 2015, records in MARC format will continue to have MeSH headings combined with the appropriate topical subheadings (650 ‡a ‡x), but geographic locations and publication types will be carried in the MARC 651 and 655 fields in the record, rather than as subfields of the MeSH heading. Catalogers in other libraries that use MeSH are encouraged to follow NLM practice in assigning their subjects.
For libraries that wish to update existing records in their catalog in the same format as they would appear in the LocatorPlus database see Instructions for Deconstructing MeSH Subjects.
See also Using Medical Subject Headings (MeSH®) in Cataloging for more detailed information.