Table 1.

American Association for the surgery of trauma kidney injury scale.^a

Gradeb	Type of injury	Description of injury
I	Contusion	Microscopic or gross haematuria, urologic studies normal
	Haematoma	Subcapsular, nonexpanding without parenchymal laceration
II	Haematoma	Nonexpanding perirenal hematma confirmed to renal retroperitoneum
	Laceration	<1.0 cm parenchymal depth of renal cortex without urinary extravagation
III	Laceration	<1.0 cm parenchymal depth of renal cortex without collecting system rupture or urinary extravagation
IV	Laceration	Parenchymal laceration extending through renal cortex, medulla, and collecting system
	Vascular	Main renal artery or vein injury with contained haemorrhage
V	Laceration	Completely shattered kidney
	Vascular	Avulsion of renal hilum which devascularizes kidney

^ahttp://www.aast.org/library/traumatools/injuryscoringscales.aspx#kidney.

^bAdvanced one grade for bilateral injuries up to grade III.