Patient information: Renal (kidney) biopsy

INTRODUCTION

A renal biopsy, also called a kidney biopsy, is a test that may be done to diagnose and determine the severity of a kidney disorder. The procedure is generally safe and can provide valuable information about your kidney disease.

This article discusses why you might need a renal biopsy, how to prepare for it, and what complications might occur. More detailed information about renal biopsy is available by subscription. (See "Indications for and complications of renal biopsy".)

REASONS FOR RENAL BIOPSY

A renal biopsy is recommended for certain people with kidney disease. It may be performed when other blood and urine tests cannot give enough information. The following are the most common reasons for kidney biopsy. You may have one or more of these problems, but not everyone with these problems needs a renal biopsy.

• Blood in the urine (called hematuria). (See "Patient information: Blood in the urine (hematuria) in adults".)

• Protein in the urine (called proteinuria) occurs in many people with kidney problems. A renal biopsy may be recommended if you have high or increasing levels of protein in the urine or if you have proteinuria along with other signs of kidney disease. (See "Patient information: Protein in the urine (proteinuria)".)

• Problems with kidney function — If your kidneys suddenly or slowly stop functioning normally, a renal biopsy may be recommended, especially if the cause of your kidney problem is unclear.

RENAL BIOPSY PROCEDURE

Preparation — Before your biopsy, you may need testing to see if you have a blood clotting abnormality or infection. To decrease the risk of bleeding, you should stop taking medicines that increase the risk of bleeding (such as aspirin, ibuprofen, or naproxen) for one to two weeks before the biopsy. Review your medicines with your healthcare provider to determine which ones are safe to continue.

If you take warfarin (Coumadin®), heparin, clopidogrel (Plavix®) or other medicines that prevent blood clots, ask your physician when to take these medications before your biopsy.

Biopsy procedure — Renal biopsy is usually performed you are awake, after you are given local anesthesia (numbing medicine) to minimize pain. The most common way to perform a biopsy is to use a needle, which is inserted through the skin and into the kidney.

In most cases, you will have an ultrasound or x-ray so that the physician knows exactly where to insert the needle. Once the needle is in the right position, the physician will take a sample of tissue from the kidney with the needle.

In some cases, a different approach is used to perform the biopsy. An open renal biopsy involves sedating you, injecting local anesthetic to prevent pain, and making a small cut in your skin, which is opened to obtain the kidney tissue.

After the biopsy, the kidney tissue will be sent to a laboratory and examined with a microscope. This microscopic examination is looking for scarring, infection, or abnormal deposits in the kidney tissue. The results of the microscopic exam are usually available within one to two weeks after the biopsy. In urgent situations, the results can be available within a few hours.

After an open or needle biopsy, you will be kept in a recovery unit for several hours to monitor for potential complications, including pain and bleeding. Most people can go home after a few hours of monitoring. Less commonly, you may need to stay in the hospital overnight.

RENAL BIOPSY COMPLICATIONS

Serious complications of renal biopsy are rare. Less serious complications can occur, and can include bleeding, pain, and development of an abnormal connection between two blood vessels (a fistula).

Bleeding — Bleeding is the most common complication of renal biopsy. Most people will notice blood in their urine for several days after a renal biopsy. If your urine is bright red or brown for longer than one week after your biopsy, call your healthcare provider.

Pain — Pain is a common problem after a renal biopsy. You will be given medications to reduce pain after the procedure, and the pain usually resolves within a few hours. If you have severe or prolonged pain, call your healthcare provider immediately.

Arteriovenous fistula — The biopsy needle can accidentally injure the walls of a nearby artery and vein, and this can lead to the development of a fistula (a connection between the two blood vessels). Fistulas generally do not cause problems and usually close on their own over time.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Blood in the urine (hematuria) in adults
Patient information: Protein in the urine (proteinuria)

Professional Level Information:
Indications for and complications of renal biopsy
Indications for renal biopsy in patients with lupus nephritis
Renal pathology test: Case presentations
Renal pathology test: Pattern recognition

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/ency/article/003907.htm)

• National Institute of Diabetes and Digestive and Kidney Diseases

      (http://kidney.niddk.nih.gov/kudiseases/pubs/biopsy/)

• National Kidney Foundation

      (www.kidney.org)

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