A kidney biopsy is done using a long thin needle put through the back (flank) into the kidney. This is called a percutaneous kidney biopsy. A tissue sample is taken and sent to a lab. It is looked at under a microscope. The sample can help your doctor see how healthy your kidney is and look for any problems. The two kidneys are found on either side of the spine, in the lower back. They help the body balance water, salts, and minerals in the blood. The kidneys also filter waste products from the blood and make urine.
The patient is expected to lie face down for at least 20-30 minutes. A towel may be placed under the upper abdomen to achieve an appropriate position. The kidney is located using the ultrasound, and then the health care provider will mark the biopsy site. A local anesthetic will be given to numb the skin at the biopsy site. A tiny incision is then made in the skin.
In addition to the numerous unique forms of lupus kidney disease, other types of kidney diseases that are not from lupus can sometimes occur in a patient with lupus. While treatment for lupus nephritis can sometimes be initiated without a kidney biopsy, more often, a biopsy is done before starting treatment. Thus, when the blood tests and the overall state of the lupus disease so require, the biopsy can define the cause of the kidney disease when it is in question. The biopsy can also guide treatment when it demonstrates the presence of such severe kidney damage that a favorable response to potentially toxic medications is unlikely.
Some patients shouldn’t have a percutaneous biopsy because they are prone to bleeding problems. These patients may still undergo a kidney biopsy through an open operation in which the surgeon makes an incision and can see the kidney to obtain a biopsy. Another method is the transjugular biopsy. To obtain the tissue sample, the needle is inserted through a catheter that enters the patient’s jugular vein at the neck. The needle threads down through the blood vessel to the right kidney in order to obtain the tissue from the inside without puncturing the outside skin of the kidney.
Kidney cancer is the eighth most common cancer in men and the tenth in women. The most common type of kidney cancer is renal cell carcinoma that forms in the lining of the renal tubules in the kidney that filter the blood and produce urine. Approximately 85 percent of kidney tumors are renal cell carcinomas. When kidney cancer spreads outside the organ, it can often be found in nearby lymph nodes, lungs, bones or liver, as well as the other kidney.
A biopsy needle will be inserted into the skin. Based on a previously determined kidney position or under direct ultrasound visualization, the needle is advanced to the surface of the kidney. The patient is then asked to take and hold a deep breath, the needle introduced into the kidney, and fired. If the physician is not using direct ultrasound guidance, he may ask the patient to take deep breaths to verify needle “embedment” before firing.