Injury Severity Score

Last Updated on November 17, 2023

Injury Severity Score is based on Abbreviated Injury Scale and is used in the assessment of injury in adults an children both. It along with pediatric trauma score are quite reliable in predicting injury measure in children.

Abbreviated Injury Scale is an anatomical scoring system where injuries are ranked on a scale of 1 to 6, with 1 being minor, 5 severe, and 6 a nonsurvivable injury.

The objective of the Abbreviated Injury Scale is to gauge threat to life associated with an injury and is not meant to represent a comprehensive measure of severity.

Detailed scoring is done as follows

Minor – 1
Moderate – 2
Serious – 3
Severe – 4
Critical – 5
Unsurvivable – 6

Injury Severity Score

The Injury Severity Score is an anatomical scoring system that provides an overall score for patients with multiple injuries to measure the injury.

Each injury is assigned an abbreviated injury score and is allocated to one of six body regions

Head
Face
Chest
Abdomen
Extremities including Pelvis
External

Out of these 6 areas, 3 most severely injured body regions are chosen and have their score squared and added together to produce the ISS score.

An example of the ISS calculation is shown below

Region	Injury Description	AIS	Square(Top Three)
Head & Neck	Cerebral Contusion	3	9
Face	No Injury	0	–
Chest	Flail Chest	4	16
Abdomen	Minor Contusion of LiverComplex Rupture Spleen	25	25
Extremity	Fractured femur	3	–
External	No injury	0	–
Total Injury Severity Score = 9+16+25=50

Maximum possible injury severity score is 75 and minimum 0.

If an injury is assigned an Abbreviated Injury Score of 6 (unsurvivable injury), the Injury Severity Score is automatically assigned to 75.

Injury Severity Score correlates linearly with mortality, morbidity, hospital stay and other measures of severity.

About Dr Arun Pal Singh

Arun Pal Singh is an orthopedic and trauma surgeon, founder and chief editor of this website. He works in Kanwar Bone and Spine Clinic, Dasuya, Hoshiarpur, Punjab.

This website is an effort to educate and support people and medical personnel on orthopedic issues and musculoskeletal health.

You can follow him on Facebook, Linkedin and Twitter

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