(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?
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.
Reasons for the Procedure
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.
Risks of the Procedure
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.