How this calculator works
Select the largest AIS severity within each of the six ISS regions. The three most severely affected regions contribute squared values. An AIS severity of 6 in any region sets ISS to 75. Injury coding requires the relevant AIS dictionary and training. The result is an estimate for information only and is not medical advice.
Formula
ISS = A² + B² + C², where A, B and C are the three highest regional AIS severities. If any regional AIS severity equals 6, ISS = 75.
Worked example
Regional maxima 4, 3, 2, 1, 0, 0 give 16 + 9 + 4 = 29. A single AIS 6 injury gives 75 regardless of the other regions.
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Frequently asked questions
Can I enter my three worst individual injuries?
Use the worst injury in each region first. ISS uses three different regions; multiple injuries in one region do not occupy multiple slots.
What if fewer than three regions are injured?
Uninjured regions contribute zero. An isolated AIS 3 injury therefore gives ISS 9.
Does AIS 6 mean any fatal injury?
No. AIS 6 is an assigned injury severity, not a code to enter simply because a patient died. The calculator does not assign AIS codes from a diagnosis.