A kidney biopsy is usually done using a long thin needle put through the back (flank) into the kidney. This is called a percutaneous kidney biopsy. A tissue sample is taken and sent to a lab. It is looked at under a microscope. The sample can help your doctor see how healthy your kidney is and look for any problems.
The two kidneys are found on either side of the spine, in the lower back. They help the body balance water, salts, and minerals in the blood. The kidneys also filter waste products from the blood and make urine.
A kidney biopsy may be done to check for kidney problems. It may also be done after other tests for kidney disease, such as blood and urine tests, ultrasound, or a computed tomography (CT) scan, show a kidney problem.
Why It Is Done
A kidney biopsy is done to:
- Find kidney disease when there is blood or protein in the urine or when the kidneys are not working well.
- Check kidney problems seen on an ultrasound or a CT scan.
- Watch kidney disease and see if treatment is working.
- Find out why a transplanted kidney isn't working well.
- Find out more information about a tumor found in the kidney.
How To Prepare
Tell your doctor if you:
Follow the instructions exactly about when to stop eating and drinking, or your test may be canceled. If your doctor has instructed you to take your medicines on the day of the test, please do so using only a sip of water.
Arrange to have someone take you home after the biopsy because you may be given a medicine (sedative) to help you relax.