Patient information: Renal (kidney) biopsy (Beyond the Basics)

INTRODUCTION

A renal biopsy, also called a kidney biopsy, is a procedure that is used to obtain small pieces of kidney tissue to look at under a microscope. It may be done to determine the cause, severity, and possible treatment 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 (Beyond the Basics)".)
• 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) (Beyond the Basics)".)
• 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, aspirin-like compounds, 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 while you are awake, after a cleansing agent is applied, and 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, x-ray, or CT scan 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 with general anesthesia, 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 abnormalities 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 or an observation unit for several hours to monitor for potential complications, including pain and bleeding. You may have blood drawn or repeat x-rays to monitor for bleeding. In some instances, you could go home after several hours of monitoring. Alternatively, you may be observed in the hospital overnight.

Once it is deemed safe for you to go home, you are not to perform any heavy lifting or vigorous exercise for one to two weeks. You should continue to avoid aspirin-like drugs or blood thinning medications for at least one week or until your physician has instructed you that it is safe to take these.

RENAL BIOPSY COMPLICATIONS

Serious complications of renal biopsy are not common. Less serious complications can occur, and can include bleeding, pain, and development of an abnormal connection between two blood vessels (a fistula). Rare complications include infection, damage to blood vessels or other organs, or urine leaks.

Bleeding — Bleeding is the most common complication of renal biopsy. Many people may notice blood in their urine for several days after a renal biopsy. More severe bleeding occurring around the kidney or into the urine is uncommon but if it occurs you may need a blood transfusion. Very rarely, it may become life threatening and possibly require a procedure or surgery to stop the bleeding. 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 can 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.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient information: Chronic kidney disease (The Basics)
Patient information: Granulomatosis with polyangiitis (Wegener’s) (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient information: Blood in the urine (hematuria) in adults (Beyond the Basics)
Patient information: Protein in the urine (proteinuria) (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

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

The following organizations also provide reliable health information.

• 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)

[1-3]