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Table of Contents: 2023 NOVEMBER–DECEMBER No. 455

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Annual MeSH Processing for 2024 MeSH

Annual MeSH Processing for 2024 MeSH. NLM Tech Bull. 2023 Nov-Dec;(455):e3.

2023 December 01 [posted]

The National Library of Medicine (NLM) is currently involved in Annual MeSH Processing (AMP) for 2024 Medical Subject Headings (MeSH). These include changing the MeSH main headings and subheadings as well as Supplementary Concept Records (SCRs) that standardize names and associated numbers for chemicals, protocols, diseases, and organisms that are not main headings. The MeSH edits include maintaining existing MEDLINE citations to conform with the 2024 version of MeSH, and other global changes.

This article collects the notable changes made to MeSH during the NLM annual maintenance for 2024:

  • MeSH Vocabulary Updated for 2024.
  • MeSH Update Reports.
  • Updated MeSH in MEDLINE Citations.

MeSH Vocabulary Updated for 2024

The MeSH Browser points to the 2024 MeSH vocabulary with a link to the 2023 MeSH vocabulary. On December 1, the default switched to 2024 and the alternate link has been routed to 2023 MeSH. Searchers should consult the Browser to find MeSH headings of interest and their relationships to other headings. The Browser contains MeSH heading records that may include Scope Notes, Annotations, Entry Terms, History Notes, Allowable Qualifiers (Subheadings), Previous Indexing, and other information. It also includes Subheading records and SCRs for substances, diseases, and organisms that are not MeSH headings.

You can download 2024 MeSH from links on the NLM Data Distribution page for MeSH Data. For additional information see Release of 2024 MeSH XML Data.

MeSH Update Reports

MeSH 2024 Update

Beginning with the release of 2023 MeSH, NLM now offers reports detailing the changes to the MeSH vocabulary. The MeSH 2024 Update reports detail the changes to MeSH terms that are performed during AMP. The MeSH 2024 Update allows users to view changes made to the MeSH vocabulary in various formats (CSV, PDF, HTML) as well as providing exportable reports (CSV, JSON, RDF, and XML). These include detailed reports regarding:

  • Descriptors and SCRs Additions.
  • Preferred Term Updates.
  • Registry Number Updates.
  • Updates Made to All Fields.
  • Descriptor and SCR Replaces.
  • Entry Combination Updates.
  • Descriptor and SCR Splits.
  • Descriptor and SCR Deletes.
  • Merge Updates.

Note: Typically, NLM does not retroactively re-index MEDLINE citations with new MeSH heading concepts. Therefore, searching PubMed for a new MeSH term tagged with [mh] or [majr] effectively limits retrieval to citations indexed after the term was introduced. Searchers may consult the MeSH database to see the previous indexing terms most likely used for a particular concept before the new MeSH heading was introduced. For terms without previous indexing information, consider the next broader term(s) in the MeSH hierarchy. For more searching guidance, see the on-demand class MeSH Changes and PubMed Searching.

Updated MeSH in MEDLINE Citations

MEDLINE citations with updated MeSH are anticipated to be in PubMed by mid-December 2023. For instruction on how to adjust historical searches to changes in MeSH, see the on-demand class MeSH Changes and PubMed Searching.

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