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NLM Classification Updated, January 26, 2017

The NLM Classification, available online at, has moved from an annual spring update to twice-yearly updates. The 2017 winter edition has been issued as of January 26, 2017.

For the winter edition, the 2017 MeSH (Medical Subject Headings) vocabulary was evaluated for inclusion in the Classification index. Several additions and changes were made to the Index and Schedules based on this review. All main index headings are now linked to the 2017 vocabulary in the MeSH Browser. Additional minor updates were made to the Index and Schedules.

Summary Statistics for the 2017 Winter Edition:

  • 92 index main headings added (82 from 2017 MeSH)
  • 137 index entries modified
  • 10 index headings deleted
  • 5 class numbers added
  • 44 class number captions or notes modified
  • No class numbers canceled

The 2017 summer version will be published in mid-to-late August 2017, and will encompass the ongoing systematic review of particular classification schedules and other miscellaneous updates. The PDF version will be published annually in conjunction with the summer version.

Contact NLM for further information, questions, or comments.

Since its founding in 1836, the National Library of Medicine has played a pivotal role in translating biomedical research into practice and is a leader in information innovation. As one of the 27 Institutes and Centers at the National Institutes of Health, NLM advances research in biomedical informatics and data science and is the world's largest medical library. Millions of scientists, health professionals and the public use NLM services every day.