Kidney failure diagnosis

If you have kidney disease and your signs and symptoms begin to indicate that the disease has progressed, your provider will likely recommend you undergo testing in order to confirm a diagnosis^[26] of kidney failure. Some tests that may be used to diagnose kidney failure include:

• Urinalysis: Urinalysis (lab analysis of a urine sample) may help reveal abnormalities indicative of kidney failure. This test may also help identify the underlying cause of your condition.
• Urine output: Your provider may recommend measuring the volume of urine you produce over a 24-hour period, which may help determine the cause of your kidney failure.
• Blood tests: One form of blood testing used to determine kidney function is a creatinine test^[27]. This test measures the level of creatinine in the blood. As healthy kidneys filter creatinine from the bloodstream, high levels of this substance can indicate declined kidney function.

A second test called a blood urea nitrogen (BUN) test^[28] measures the level of urea (another waste filtered by healthy kidneys) in the blood.

• Imaging tests: Imaging tests, such as ultrasound, may be used to produce images of your kidneys.
• Kidney biopsy: This procedure involves removing a sample of kidney tissue for testing (biopsy). This is often done with patients under local anesthesia.

A kidney biopsy is performed using a long, thin needle that is inserted into the kidney through the skin to remove a sample. This sample is then sent to a lab for testing, which can help determine the severity of a patient’s kidney disease.