In 2002 the group of experts (Acute Dialysis Quality Initiative – ADQI) developed the definition of acute renal failure (ARF) and created the system of its heaviness stratification (RIFLE-criteria). In 2004 the definition “acute renal impairment” (ARI) was introduced and in 2007 the research group Acute Kidney Injury Network (AKIN) offered the criteria system of diagnostics and evaluation of condition intensity (AKIN-criteria), that is modification of RIFLE. Both systems made a good showing in practice in prognostics of ARI development and its outcomes at critical patients. At the same time RIFLE and AKIN use primarily was not planned for use at patients with acute primary parenchymatous kidney injury, that embarrassed their introduction to wide nephrological practice. In the present article the modificated system AKIN (that is more suitable for clinical use) is presented.

Keywords: classification, definition, acute renal failure, acute kidney injury