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NLM Classification 2017: Worldwide source of medical library classification

Scope of Revision of the 2019 Summer Edition


The major focus of the 2019 summer edition was the systematic review of the following schedules: QW (Microbiology. Immunology) and QX (Parasitology). In addition to the systematic reviews of the QW and QX schedules, other minor additions and changes were made.


Summary Statistics for the 2019 Summer Edition

  • 57 class numbers added
  • 8 schedule outline headers added
  • 109 class number captions or notes modified; indentation levels changed; group labels modified
  • 19 schedule outline headers modified
  • 42 class numbers canceled
  • 3 schedule outline headers deleted
  • 99 index main headings added
  • 481 index entries modified
  • 115 index headings deleted

Systematic Reviews for the 2019 Summer Edition


Highlights from the QW (Microbiology. Immunology) Review

The QW analysis revealed some inconsistency and overlap between parts of the QW and WD (Disorders of Systemic, Metabolic or Environmental Origin, etc.) schedules. For example, both QW and WD had areas with the header Hypersensitivity. Since Hypersensitivity is an immunological response, it is preferable to classify all the works in the QW Immunology Section.

A major partial review of the WD schedule was conducted to consolidate certain subjects in the QW and other schedules. As a result, several WD class numbers were canceled and some new QW numbers were created. Also, two 19th century schedule numbers were made obsolete: WDB Hypersensitivity and WDC Animal poisons. Plant poisons.

Two new numbers were created in other schedules: QV 762 Toxic plants and WA 700 Foodborne diseases (General or not elsewhere classified).

Highlights from the QX (Parasitology) Review


The analysis revealed that, although the QX schedule is labeled as Parasitology, it contained numbers for many different organisms some of which are not parasites. For example, QX 675 indicates it is for Mollusca, but not all Mollusca are parasites. A work on the biology of the squid should not be classed in QX but in the Library of Congress QL classification. As a result of the analysis, “Disease Vectors” was added to the QX Schedule Header to indicate this schedule is about invertebrates and their relationship to medicine. Several new class numbers were created for specific invertebrates. The class numbers in the section on unicellular Eukaroyta were cancelled and reclassed in new numbers in the QW schedule. Related index terms were updated to reflect the change in classification and to provide LC classification when not medically related.


Other 2019 Summer Edition Changes

Examples of additional changes made:

Classification of Laws Related to Food or Beverages

  • WA 697 Pure food laws was broadened to include laws and discussion of laws related to specific types of foods or beverages. It now has a (Table G) annotation to allow for geographic breakdown. WA 697.1 was created for works with no geographic breakdown
  • The notes at WA 32, WA 33, WA 701, and WN 612 were adjusted to provide guidance about classification of laws related to food or beverages
  • Several food index terms were modified to provide guidance about the classification of food legislation

Classification of Laws Related to Anatomy

  • QS 132 Laws concerning dissection. Discussion of laws was broadened to include laws on anatomy. It now has a (Table G) annotation to allow for geographic breakdown. QS 132.1 was created for works with no geographic breakdown
  • QS 133 and QS 133.1 were created for discussion of laws on anatomy

Index Changes for Class numbers that Only Point to a Main Schedule Number

A project was conducted to eliminate alpha only class numbers from the index. Where a specific class number or range was available, it was added. Otherwise, appropriate subindex terms were added with specific class numbers. For example, Bible BS was changed to Bible BS 1-680. Eye WW had the alpha only removed and a subindex term General WW 100 added to the list of subindex terms.


Table G Addition

  • GH6--Holy Roman Empire was added.