Abbreviated Injury Scale (AIS)
Simple educational helper for AIS severity (1–6) by body region and example injury type
For educational use only. This tool does not implement the full AIS dictionary and must not be used for official trauma registry coding, billing, or research. Please consult the official AAAM AIS manual and trained coders for definitive coding.
Select injury details
AIS severity: –
Severity label: Not yet calculated
Select a body region and example injury type, then click “Show AIS severity” to see an approximate AIS severity level.
AIS is a proprietary, dictionary-based injury coding system developed by the Association for the Advancement of Automotive Medicine (AAAM). This tool only illustrates broad severity categories (AIS 1–6) and does not substitute for the official AIS manual or certified training.
What is the Abbreviated Injury Scale (AIS)?
AIS was originally developed by the Association for the Advancement of Automotive Medicine (AAAM) in the 1970s and has been updated several times (notably AIS 1998, 2005, and 2008 revisions). It is a dictionary-based system: each specific injury description (e.g. “splenic laceration, major, >3 cm depth”) has a unique AIS code. The final digit of that code is the AIS severity from 1 to 6.
AIS considers injuries across 9 regions (depending on version), for example:
- Head
- Face
- Neck
- Thorax (chest)
- Abdomen / pelvic contents
- Spine
- Upper extremity
- Lower extremity / pelvis
- External / skin
For each coded injury, AIS assigns a severity level:
- AIS 1 – Minor
- AIS 2 – Moderate
- AIS 3 – Serious
- AIS 4 – Severe (survival probable)
- AIS 5 – Critical (survival uncertain)
- AIS 6 – Maximal / currently untreatable (unsurvivable injury in most contexts)
Higher numbers indicate greater anatomical injury severity, not necessarily physiological derangement at that moment.
What AIS is used for
- Trauma research and benchmarking – forms the basis of ISS and NISS, used to compare trauma centre performance.
- Risk adjustment – helps account for injury severity when analysing outcomes like mortality or ICU admission.
- Registry coding – standardises description of injuries across centres and countries.
Important limitations
- AIS coding requires an official coding manual and usually specialist training.
- It is not meant to be guessed at the bedside from a brief description.
- It describes anatomical damage, not physiology (shock, GCS, etc.) or comorbidities.
- Different AIS versions exist; the exact codes and sometimes severity of particular injuries can change between versions.
Because AIS is dictionary-based, there is no simple formula to “calculate” AIS from scratch. Any web tool can only help with simple mapping / educational examples, not replace the official manual or a trained coder.
