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 April 20, 2004 [posted]
 NLM Classification 2004 Edition Now Available

drop cap letter for t he 2004 edition of the NLM Classification incorporates all additions and changes to the schedules and index from August 2003 through April 2004.


New class numbers were added and existing class numbers were canceled as needed to reflect changes in MeSH and the biomedical and related sciences literature cataloged.

Class Numbers Added—2004

New Number Class Name Former Number
WA Public Health
WA 420 Violence in the workplace (General or not elsewhere classified) Various Numbers
WA 550-550.1 Family planning services HQ 763.5-767.7
WD Disorders of Systemic, Metabolic or Environmental Origin, etc.
WD 200.5.G6 Glucose metabolism disorders WD 200
WX Hospitals and Other Health Facilities
WX 40-WX 40.1 Hospital accreditation. Licensure. Standards WX 15
WY Nursing
WY 100.2 Moving and lifting of patients Various numbers
WZ History of Medicine
WZ 112.5.O75 Orthopedists WZ 112

Class Numbers Canceled—2004

Canceled Number Class Name Now Classed in
QW 149 Rickettsiales and chlamydiales QW 150; QW 152
WK 187 Synthetic hormones WK 150-190, etc.
WK 757 Synthetic substitutes for cortical hormones WK 755

Other Changes to the Schedule

  • For the first time, canceled class numbers appear in normal sequence within the current schedules for informational purposes. These numbers are in square brackets, clearly marked with the caption: "This number not used." A compilation of these numbers is provided in Canceled Class Numbers.
  • Lengthy notes at the beginning of each schedule have been reformatted to improve readability.
  • Selected class number captions were augmented to clarify their scope, e.g., at WB 400, Nutrition Therapy was added to Dietetics. Diet therapy.
  • Selected class number captions were changed to reflect changes in MeSH terminology, e.g., at QV 350, Antibiotics was changed to Anti-bacterial agents.
  • Various instructional notes were added or modified to clarify classification practices, e.g., at WZ 23, "Classify here histories of institutes devoted to medical history; classify other institutes with the field" was added.


MeSH Additions, Changes, and Deletions for 2004—Classification Implications

  • Ninety-four (94) new main index entries were created, sixty-five (65) of which are from the 2004 MeSH; the remainder are MeSH terms from previous years.
  • Numerous main index entries and cross references were changed or deleted to reflect changes in the MeSH vocabulary. Those entries that were changed are a subset of Changed Descriptors—2004. Those entries that were deleted are a subset of Deleted Descriptors—2004. In particular, major categories of index terms affected by MeSH changes include:

    Racial Stock and Ethnic Group terms, e.g.,
    Negroid Race to African Continental Ancestry Group
    Drugs and Chemicals, e.g.,
    Antibiotics to Anti-Bacterial Agents
    Plant terms, e.g.,
    Mustard to Mustard Plant
    Bacteria terms, e.g.,
    Budding and Appendaged Bacteria to Bacteria

Instructional Notes to Clarify NLM Classification Practices

  • Various instructional notes were added to index entries to clarify classification practices. Major categories of index terms affected include:
    Nutrition—Specific guidance is given for classification of infants, children, and/or adolescents.
    Traditional medicine—Current practice (WB) is clearly differentiated from historical practice (WZ)
    Biography vs. history—Collective biography of physicians, etc. (WZ 150) is distinguished from non-biographical history (WZ 80.5)
    Patient transfer vs. lifting of patients—Guidance is given for classification of administrative transfers (WX 158) versus general patient lifting procedures (WY 100.2)

Other Changes to the Index

  • Index entries with Library of Congress (LC) HM schedule numbers were maintained to reflect major changes in the LC schedule.

  • All index entries pertaining to the schedule additions and changes were modified.

To learn more about the NLM Classification, see the Fact Sheet.

By Sharon R. Willis
Cataloging Section, Technical Services Division

black line separating article from citation

Willis SR. NLM Classification 2004 Edition Now Available. NLM Tech Bull. 2004 Mar-Apr;(337):e5.


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Last updated: 12 April 2012