The evaluation of kidney failure is typically based on how long the condition has been present. The evaluation of longstanding or chronic kidney failure is performed in the outpatient nephrology clinic and involves blood and urine tests. Some patients require further testing in radiology and/or follow-up blood or urine testing based on the results of the initial evaluation.

Unexplained or rapid loss of kidney function, called acute kidney failure, is a more urgent problem and requires admission to the hospital to define the cause and appropriate therapy.