The Cribari Matric is used to assess undertriage and overtriage in a trauma center. It is comparable to the true positive and false negative rates.

Axes for 2x2 matrix:

(1) major trauma (ISS > 15, positive NFTI, or other criteria) vs minor trauma

(2) full trauma team activation or not



Major Trauma (ISS > 15)

Minor Trauma (ISS <= 15)

Full Team Activated



Full Team Not Activated




undertriage = false negative rate =

= (number with full team not activated AND major trauma) / (total number with full trauma team not activated) =

= c / (c + d)


overtriage = false positive rate =

= (number activated and minor trauma) / (total with full trauma team activated) =

= b / (a + b)


correctly triaged =

= (a + d) / (a + b + c + d)

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