Kidney Biopsy

Test Overview

A biopsy is a procedure to collect small pieces of tissue to look at under a microscope. A kidney biopsy may be done to check for problems or when other tests show a kidney problem. For example, you may get one if a test shows that you have blood or protein in your urine. The biopsy is usually done by putting a long, thin needle through the back and into the kidney. The doctor may do several biopsies to make sure there is a good sample.

The doctor may use ultrasound or a CT scan to guide the needle during the biopsy. The area will be made numb during the procedure.

The biopsy itself will take 15 to 30 minutes. The whole procedure will take about an hour.

After the procedure, you'll stay in the hospital or surgery center for several hours to make sure there are no problems. Most people can go home the same day. You may need someone to drive you home.

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

Procedures can be stressful. This information will help you understand what you can expect. And it will help you safely prepare for your procedure.

Preparing for the procedure

• You may need to stop eating and drinking before the day of the procedure. If this is the case, your doctor will tell you what to do.
• Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
• Understand exactly what procedure is planned, along with the risks, benefits, and other options.
• Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your procedure. Your doctor will tell you if you should stop taking any of them before the procedure and how soon to do it.
• If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your procedure. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.
• Make sure your doctor and the hospital have a copy of your advance directive. If you don't have one, you may want to prepare one. It lets others know your health care wishes. It's a good thing to have before any type of surgery or procedure.

How It Is Done

A kidney biopsy is done in a clinic or a hospital.

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 (I.V.) 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.

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.

How long the test takes

The biopsy itself will take 15 to 30 minutes. The whole procedure will take about an hour.

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.

Risks

There is a small chance for serious problems from a kidney biopsy, but they are rare.

• Bleeding into the muscle, which can cause soreness.
• Bleeding into the kidney.
• Infection of the skin at the biopsy site.
• Pneumothorax (collapsed lung) .
• Puncturing a major blood vessel, which may need blood transfusions, renal angiography and embolization, or surgery. This is very rare.

Results

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.

Kidney biopsy

Normal:	The structure and cells of the kidney look normal. There are no signs of inflammation, scar tissue, infection, transplant rejection, or cancer.
Abnormal:	The sample may show signs of scarring due to infection, poor blood flow, glomerulonephritis, a kidney infection (pyelonephritis), or signs of other diseases that affect the body, such as systemic lupus erythematosus.
	Kidney tissue may show tumors that were not expected, such as Wilms' tumor (which occurs in early childhood) and renal cell cancer (which is most common after age 40).
	Kidney tissue shows signs of transplant reactions, rejection, or failure.