Which statement about AIS scoring and ISS calculation is correct?

• A. AIS measures overall body injury severity; ISS sums all injuries
• B. AIS measures patient physiologic response
• C. AIS assesses individual injuries; ISS aggregates top three AIS scores (squared)
• D. AIS predicts long-term outcomes only

Answer: (C)

The main idea is that AIS assigns a severity score to each individual injury, not to the whole patient, and ISS uses those per-injury scores to produce an overall severity by focusing on the three most severe injuries across different body regions, squaring each score and adding them together. This approach weights more severe injuries more heavily, which is why the combination of “assesses individual injuries” with “aggregates the top three AIS scores (squared)” is the correct description. For example, if the top regional AIS scores are 4, 3, and 2, the ISS would be 4^2 + 3^2 + 2^2 = 29. The other statements misstate AIS or ISS by implying AIS measures physiology or overall body severity, or that AIS solely predicts long-term outcomes.