Schedules are topical groupings of classification numbers. There are 36 schedules which denote six (6) broad subject categories:

Schedules in the NLM Classification

Schedule	Header
Preclinical Sciences (QS–QZ)
QS	Human Anatomy
QT	Physiology
QU	Biochemistry. Cell Biology and Genetics
QV	Pharmacology
QW	Microbiology. Immunology
QX	Parasitology. Disease Vectors
QY	Clinical Laboratory Pathology
QZ	Pathology
General Health and Medicine (W–WB)
W	General Medicine. Health Professions
WA	Public Health
WB	Practice of Medicine
Communicable Diseases; Medicine in Selected Environments (WC–WD)
WC	Communicable Diseases
WD	Medicine in Selected Environments
Body Systems (WE–WL)
WE	Musculoskeletal System
WF	Respiratory System
WG	Cardiovascular System
WH	Hemic and Lymphatic Systems
WI	Digestive System
WJ	Urogenital System
WK	Endocrine System
WL	Nervous System
Specialty Areas (WM–WY)
WM	Psychiatry
WN	Radiology. Diagnostic Imaging
WO	Surgery
WP	Gynecology. Andrology
WQ	Obstetrics
WR	Dermatology. Integumentary System
WS	Pediatrics
WT	Geriatrics
WU	Dentistry. Oral Surgery
WV	Otolaryngology
WW	Ophthalmology
WX	Hospitals and Other Health Facilities
WY	Nursing
History (WZ; 19th Century)
WZ	History of Medicine. Medical Miscellany
19th Century Schedule	All works published between 1801–1913

Example Schedule Page in Online Classification

The following is a screenshot of the online NLM Classification. This shows:

• Schedule - WX
• Schedule Header - WX Hospitals and Other Health Facilities
• Range Header - Reference Works, General Works
• Classification Number - WX 1
• Classification Note - Organizations. Societies (General or not elsewhere classified) (Cutter from name of organization or society) (Table-G) (Monographs and Serials) Includes membership lists and administrative reports issued serially or separately. Classify directories in WX 22. Classify other serials issued by societies in W1.

Notes about LCC Usage

Library of Congress Classification (LCC) schedules augment the NLM Classification for subjects related to medicine. Some LCC numbers or range of numbers appear in the NLM Classification Index. Although LCC numbers are verified against the LCC schedules periodically, the pertinent LCC schedules must be consulted since the numbers may change over time.

In some cases, a term is indexed to numbers in both the NLM Classification and the LCC schedules, depending on emphasis:

• If medical aspects predominate, classify the work in the NLM schedule.
• If social, religious, or other aspects predominate, classify in the LCC schedule.
• In case of doubt, prefer the NLM schedule.

There are special cases where the NLM Classification uses different classes than the LCC schedules. The following are LCC schedules that are not used by NLM, and what NLM uses instead:

NLM Classification Schedules Different than LCC

Topic	Library of Congress Classification (LCC)	National Library of Medicine (NLM) Classification
Human Anatomy	QM	QS
Microbiology	QR	QW
Medicine	R	QT-QZ; W-WZ

Generally, these LCC schedules supplement the NLM Classification for non-medical topics:

• Philosophy. Psychology. Religion (B)
• Geography. Anthropology. Recreation (G)
• Social Sciences (H)
• Political Science (J)
• Education (L)
• Science (Q)
• Animal Culture (SF)
• Bibliography. Library Science (Z)

The NLM also uses certain LCC schedules with restrictions:

LCC Schedules that have NLM Classification Restrictions

Schedule	Library of Congress Classification (LCC)	NLM Classification Restriction
D–E	History	Used mainly for wars
K	Law	Rarely used
QD	Chemistry	Use QU or QV for biochemistry or pharmacology
QH	Natural History. Biology (General)	Use QU, etc. for biomedical aspects
QK	Botany	Use QV 766–770 for medicinal plants; or WB 925 for Herbal Medicine
QP	Physiology	Restricted to wild animals
T	Technology	Use QT for biomedical engineering
U	Military Science	Use only for administrative aspects
V	Naval Science	Use only for administrative aspects