Urology Tests and Procedures
(Biopsy-Kidney, Renal Biopsy, Biopsy-Renal, Needle Aspiration of the Kidney, Percutaneous Kidney Biopsy)
What is a kidney biopsy?
A biopsy is a procedure performed to remove tissue or cells from the body for examination under a microscope. During a kidney biopsy, tissue samples are removed with a special needle to determine if cancer or other abnormal cells are present, or to determine how well the kidney is working.
There are two types of kidney biopsies:
- needle biopsy - After a local anesthetic is given, the physician inserts the special biopsy needle into the kidney to obtain a sample. Ultrasound (high-frequency sound waves) or computerized tomography (CT scan) may be used to guide the biopsy needle insertion. Most kidney biopsies are performed using this technique.
- open biopsy - After a general anesthetic is given, the physician makes an incision in the skin and surgically removes a piece of the kidney. Depending upon the lab findings, further surgery may be performed.
If your physician wants to sample a specific area of the kidney, the biopsy may be performed in the radiology department, guided by ultrasound, fluoroscopy, or computed tomography (CT scan, a combination of x-rays and computer technology).
Other related procedures that may be used to assess the kidneys include kidney, ureters, and bladder (KUB) x-ray, CT scan of the kidneys, kidney scan, renal ultrasound, renal angiogram, antegrade pyelogram, retrograde pyelogram, intravenous pyelogram, and renal venogram. Please see these procedures for additional information.
How do the kidneys work?
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The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.
The kidneys and urinary system keep chemicals, such as potassium and sodium, and water in balance, and remove a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.
Two kidneys, a pair of purplish-brown organs, are located below the ribs toward the middle of the back. Their function is to:
- remove liquid waste from the blood in the form of urine
- keep a stable balance of salts and other substances in the blood
- produce erythropoietin, a hormone that aids the formation of red blood cells
- regulate blood pressure
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule.
Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
A kidney biopsy may be performed to:
- determine the reason for poor kidney function
- determine if a tumor in the kidney is malignant (cancerous) or benign
- evaluate how well a transplanted kidney is working
There may be other reasons for your physician to recommend a kidney biopsy.
As with any surgical procedure, complications can occur. Some possible complications may include, but are not limited to, the following:
- bruising and discomfort at the biopsy site
- prolonged bleeding from the biopsy site, in the urine, or internally
- puncture of adjacent organs or structures
- infection near the biopsy site
If the kidney biopsy is performed with the aid of x-ray technology, the amount of radiation used is considered minimal. Therefore, the risk for radiation exposure is low.
If you are pregnant or suspect you may be pregnant, you should notify your physician.
Kidney biopsy may be contraindicated in persons with an active kidney infection, certain bleeding conditions, uncontrolled hypertension (high blood pressure), or with only one functioning kidney.
There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
- Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
- You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear.
- In addition to a complete medical history, your physician may perform a complete physical examination to ensure you are in good health before undergoing the procedure. You may undergo blood tests or other diagnostic tests.
- Notify your physician if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
- Notify your physician of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
- Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
- If you are pregnant or suspect that you are pregnant, you should notify your physician.
- You may be asked to fast before the procedure, generally after midnight. Your physician will give you specific instructions.
- You may receive a sedative prior to the procedure to help you relax. Because the sedative may make you drowsy, you will need to arrange for someone to drive you home.
- Based upon your medical condition, your physician may request other specific preparation.
A kidney biopsy may be performed on an outpatient basis or as part of your stay in a hospital. The kidney biopsy may be performed in a procedure room, in a hospital bed, or in the radiology department. Procedures may vary depending on your condition and your physician’s practices.
Generally, a kidney needle biopsy follows this process:
- You will be asked to remove clothing and will be given a gown to wear.
- An intravenous (IV) line may be started in your arm or hand.
- You will be positioned on your stomach so that the physician can easily reach the kidney. A pillow may be used to hold you in the correct position. If you have a transplanted kidney, you will be positioned on your back.
- The skin over the biopsy site will be cleansed with an antiseptic solution.
- You will feel a needle stick when the local anesthetic is injected. This may cause a brief stinging sensation.
- You will need to lie still during the procedure.
- Ultrasound may be used to guide the biopsy needle insertion.
- You will be asked breathe in and hold your breath while the physician inserts the biopsy needle into the kidney. Holding your breath prevents movement of the diaphragm, which may interfere with the placement of the biopsy needle. You should lie quietly without moving.
- You may feel discomfort or pressure when the physician obtains the sample.
- There may be more than one puncture performed if the physician needs more than one tissue sample. If so, the same puncture process will be repeated.
- The biopsy needle will be withdrawn and firm pressure will be applied to the biopsy site until the bleeding has stopped.
- A sterile bandage/dressing will be applied.
- The kidney tissue sample will be sent to the lab for examination.
Your recovery process will vary depending upon the type of procedure performed and your physician’s practices. You may be taken to the recovery room for observation if your procedure was done in a procedure room or in the radiology department. Once your blood pressure, pulse, and breathing are stable and you are alert, you may be taken to a hospital room or discharged to your home.
You will be asked to lie on your back for several hours. A nurse will check your urine for signs of bleeding. You may have blood tests to monitor for internal bleeding. You may be discharged later the same day or the next day.
The biopsy site may be tender or sore for several days after the biopsy. Take a pain reliever for soreness as recommended by your physician. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only recommended medications.
Notify your physician to report any of the following:
- blood in your urine after the first 24 hours
- fever and/or chills
- redness, swelling, or bleeding or other drainage from the biopsy site
- increased pain around the biopsy site or elsewhere
- feeling faint
You may resume your usual diet unless instructed differently. Your physician may ask you to rest for a day or two and to avoid strenuous physical activity for several days. You should not perform any type of “bouncing” activities such as jogging, aerobics, playing tennis, or horseback riding for a couple of weeks to prevent bleeding of the biopsy site.
Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.