Comparison between the WHO ICD-9 and ICD-10 classifications
| ICD-9 | ICD-10 | |
| Name of classification | International Classification of Diseases | International Statistical Classification of Diseases and Related Health Problems |
| No of volumes | (1) Volume 1—tabular list | (1) Volume 1—tabular index |
| (2) Volume 2—alphabetical index | (2) Volume 2—instruction manual | |
| (3) Volume 3—alphabetical index | ||
| No of sections vs chapters | 17 sections (001–099) | 21 chapters (A00-Z99) |
| Except for U codes | ||
| U00–U49: reserved for the provisional assignment of new diseases of unknown causes | ||
| U50–U99: for research purposes | ||
| Supplementary classifications | Two supplementary classifications | No supplementary classifications (prior supplementary classifications are now their own chapters) |
| (1) External causes of injury and poisoning (E800–E999) | ||
| (2) Factors influencing health status and contact with health services (V01–V82) | (1) Chapter XX: external causes of morbidity and mortality (V01–Y98) | |
| (2) Chapter XXI: factors influencing health status and contact with health services | ||
| Categories | 909 | 2036 |
| Subcategories | 5161 | 12 159 |
| Total codes | 6882 | 12 420 |
Source: Jetté N, et al.22