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:
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.
You will have blood tests done before the kidney biopsy to see whether you have any bleeding problems or blood clotting disorders. You may also have an ultrasound test or CT scan of the kidney to show the best place in your kidney to put the biopsy needle.
You will be asked to sign a consent form that says you understand the risks of the test and agree to have it done.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
How It Is Done
A kidney biopsy is done by a urologist, nephrologist, or a radiologist in a clinic or a hospital. A kidney biopsy is often done by a radiologist using ultrasound, fluoroscopy, a CT scan, or magnetic resonance imaging (MRI) to help guide the biopsy needle.
You will need to take off all or most of your clothes. You will wear a gown. Before the biopsy, you may be given a sedative through an intravenous (IV) line in a vein in your arm. The sedative will help you relax and lie still during the biopsy.
During the test
You will be asked to lie on an examination table. A sandbag, a firm pillow, or a rolled towel will be placed under your body to support your belly. It is very important that you follow your doctor's directions about breathing, holding your breath, and lying still while the biopsy is being done.
Your doctor will examine your back and may mark the biopsy site by making a slight dent in your skin with a pencil or tool. The biopsy may be done on either the right or the left kidney. The site will be cleaned with a special soap. Your doctor then gives you local anesthetic to numb the area where the biopsy needle will be inserted.
Your doctor puts the biopsy needle through the skin while looking at your kidney with ultrasound or another imaging technique. You will be asked to hold your breath and stay very still while the needle is put into the kidney.
The needle is removed after the tissue sample is taken. Pressure is put on the biopsy site for several minutes to stop the bleeding. Then a bandage is put on the site. The biopsy takes 15 to 30 minutes.
After the test
After the biopsy, you will rest in bed for 6 to 24 hours. Your pulse, blood pressure, and temperature will be checked often after the biopsy.
If no problems develop, you can go home. To prevent bleeding at the biopsy site, you will be told to lie down in a certain position for the next 12 to 24 hours. You may eat your normal diet. Do not take aspirin or anti-inflammatory medicines for a week after the biopsy. You may do your regular activities, but do not do strenuous activities, such as heavy lifting, hard running, motorcycle riding, contact sports, or other activities that might jar or jolt your kidney, for 2 weeks after the biopsy.
How It Feels
You may feel a brief sting or pinch when the numbing medicine is put in. When the biopsy needle is put in, you may feel a sharp pain for a few seconds.
It is normal to feel some muscle soreness in the area of the biopsy for 2 to 3 days after the biopsy. You may have a small amount of bleeding on the bandage after the biopsy. Talk to your doctor about how much pain and bleeding you can expect. Many people will have bright red blood in their urine for the first 24 hours after the biopsy; this is expected.
There is a small chance for serious problems from a kidney biopsy, but they are rare.
After the biopsy
After the biopsy, call
After the biopsy, call your doctor immediately if you:
A kidney biopsy is done by inserting a long needle through the back (flank) or belly to remove a sample of kidney tissue.
Biopsy results are ready in 2 to 4 days. If tests are done to find infections, it may take several weeks for the results to be ready.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
What To Think About
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