Recommended categories of organ system/region for illnesses
| Organ system/Region | ICD-11 | OSIICS | SMDCS | Notes |
| Cardiovascular | 11 | MC | CV | |
| Dermatological | 14 | MD | DE | |
| Dental | (13) | MT | DT | |
| Endocrinological | 05 | MY | EN | |
| Gastrointestinal | (13) | MG | GI | |
| Genitourinary | 16 | MU | GU | Includes renal, obstetrical, gynaecological. |
| Haematological | 03 | MH | BL | |
| Musculoskeletal | 15 | MR | MS | Includes rheumatological conditions. |
| Neurological | 08 | MN | NS | |
| Opthalmological | 09 | MO | OP | |
| Otological | 10 | ME | OT | Ear only. |
| Psychiatric/psychological | 06 | MS | PS | |
| Respiratory | 12 | MP | RE | Includes nose and throat. |
| Thermoregulatory | (22) | MA | TR | |
| Multiple systems | MX | MO | ||
| Unknown or not specified | MZ | UO |
ICD, International Classification of Disease; OSIICS, Orchard Sports Injury and Illness Classification System; SMDCS, Sport Medicine Diagnostic Coding System.