Table 1.

Diagnostic criteria of prerenal and intrinsic AKI in the absence of a histological diagnosis

Clinical Criteria	Prerenal AKI	Intrinsic AKI
Category A
response to volume repletion	Rapid decrease of creatine with convergence to baseline levels	No reconstitution of renal function
Category B
history compatible	Dehydration, loss of fluid, e.g., by gastroenteritis, heart failure, liver failure, inadequate use of diuretics, etc.	Prolonged shock, exposition to nephrotoxins, extrarenal suggestive symptoms like pulmorenal syndrome, etc.
physical findings compatible	Low blood pressure, low jugular pulse, tachycardia, orthostatic changes, poor skin turgor	Absence of signs of dehydration, cardiac monitoring shows adequate volemia
urine examinations	Absence of proteinuria, hematuria, and leukocyturia	Proteinuria and/or hematuria and/or leukocyturia

The criteria of category A are obligatory and criteria of category B are optional for the diagnosis of prerenal or intrarenal AKI. Diagnosis of prerenal AKI required two criteria of category B and the obligatory criterion of category A. Hepatorenal syndrome, cardiorenal syndrome, and bilateral renal artery stenosis were regarded as prerenal AKI independent of these criteria. AKI, acute kidney injury.