| W | Medical Profession |
| WA | Public Health |
| WB | Practice of Medicine |
| WC | Communicable Diseases |
| WD100 | Nutrition Disorders |
| WD200 | Metabolic Diseases |
| WD300 | Diseases of Allergy |
| WD400 | Animal Poisons |
| WD500 | Plant Poisons |
| WD600 | Diseases Caused by Physical Agents |
| WD700 | Aviation and Space Medicine |
| WE | Musculoskeletal System |
| WF | Respiratory System |
| WG | Cardiovascular System |
| WH | Hemic, Lymphatic Systems |
| WI | Digestive System |
| WJ | Urogenital System |
| WK | Endocrine System |
| WL | Nervous System |
| WM | Psychiatry |
| WN | Radiology |
| WO | Surgery |
| WO200 | Anesthesia |
| WP | Gynecology |
| WQ | Obstetrics |
| WR | Dermatology |
| WS | Pediatrics |
| WT | Geriatrics, Chronic Disease |
| WU | Dentistry, Oral Surgery |
| WV | Otolaryngology |
| WW | Ophthalmology |
| WX | Hospitals/Health Facilities |
| WY | Nursing |
| WZ | History of Medicine |
