Common causes are low blood flow to the kidneys (such as caused by low blood pressure), drugs that damage the kidneys, and severe bodywide infections.
People have no symptoms unless kidney injury is severe.
Diagnosis is based mainly on the results of laboratory tests.
Treatment is directed at the cause, for example, stopping drugs that are damaging the kidneys, giving intravenous fluids to raise blood pressure, and giving antibiotics to treat infection.

Injury to the kidney tubule cells harms the ability of the kidneys to filter the blood. Thus, waste products such as urea and creatinine build up in the bloodstream.
(See also Overview of Kidney Filtering Disorders.)