Tiny blood vessels within the kidneys filter the blood that flows through them. Acute renal failure is caused either by reduced blood supply to the kidneys or by damage due to the kidneys caused by disease. People who have been badly burned, who have had severe bleeding, who are dehydrated, or who are very ill may go into shock. Shock causes dangerously low blood pressure and blood flow and may lead to kidney damage. Your doctor will take note of your symptoms and examine you.
Some tests are necessary to make the diagnosis.
Urine and blood tests can show how well your kidneys are functioning. Your doctor will also look for the underlying cause of the kidney failure. Medical imaging, which can include special x-rays, and ultrasound tests may be done to show the size of your kidneys and to detect any blockages. A biopsy, a test in which tissue or cell samples are taken and examined, is sometimes needed. Your kidneys may work normally again when the underlying cause is treated.