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AAST Kidney Injury Scale

AAST-OIS 2018 revision (Kozar et al.)

Grades renal trauma on contrast CT according to the 2018 revision of the AAST organ injury scale, including the vascular-injury upgrade rules.

Also searched as: trauma · renal · injury grading · CT · renal injury · grading

CT findings present (select all that apply)

The highest-grade applicable finding determines the AAST grade.

Both kidneys are injured (bilateral injuries)

2018 rule: advance one grade for bilateral injuries, but not beyond grade III.

Lower concern
No injury findings selected
  • None of the listed findings is present — on this assessment the organ shows no traumatic injury pattern, so no AAST grade applies (grade I is the mildest injury).
  • If any listed finding is present, select it; the single highest-grade criterion determines the AAST grade.

How this tool works

The AAST kidney injury scale classifies renal trauma from grade I (contusion or limited subcapsular hematoma) to grade V (shattered or devascularized kidney). The 2018 revision made vascular findings explicit: any renal injury accompanied by a pseudoaneurysm or arteriovenous fistula, or by active bleeding still contained within the Gerota fascia, is at least grade III, while bleeding beyond the Gerota fascia, collecting-system disruption, segmental vessel injury, and thrombotic infarction are grade IV. The grade is set by the single most severe finding, and when both kidneys are injured the grade is advanced by one, up to grade III. The scale describes anatomy only and is interpreted together with the patient's hemodynamic status.

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