Kidney Biopsy

Kidney biopsy.

• To determine the cause of protein or blood in the urine (proteinuria and hematuria).
• To monitor the effectiveness of treatment.

A tiny sample of kidney tissue is obtained with a long needle and examined by a pathologist under the microscope for damage or abnormalities.

• You discontinue any nonsteroidal anti-inflammatory drugs, including aspirin and ibuprofen, 10 to 14 days before the test, as these drugs impair the blood's clotting ability.
• You have initial blood tests to screen for bleeding abnormalities. If you have clotting problems, you may be admitted to the hospital the evening before the biopsy for treatment to diminish this, or the biopsy may be canceled.
• You fast on the day of the biopsy to avoid any potential stomach upset that sometimes accompanies anxiety about the procedure.

• You lie facedown on a bed or stretcher while your kidneys are visualized using an X-ray, ultrasound, or CT scan to guide the nephrologist in inserting the needle.
• The area just under your ribs is then anesthetized with novocaine.
• A thin, 4- to 6-inch biopsy needle is passed through your skin down to your kidney.
• You hold your breath while a tiny piece (about ¹/₄ of an inch long) of kidney tissue is obtained. Sometimes this procedure must be repeated a few times until an adequate specimen is obtained.
• No incision is made and no stitches are required.

• You will be kept in bed for several hours after the biopsy to prevent excessive internal bleeding, or you may be admitted to the hospital to monitor possible bleeding.
• Your blood pressure is monitored frequently because a drop can indicate abnormal bleeding.
• One out of three patients experiences red urine in the first 24 hours or so (this is not a sign of excessive bleeding).
• Your blood count and blood pressure are checked 12 to 24 hours after the biopsy. If they are stable, you will be discharged.
• You must avoid any "bouncing activity" (e.g., aerobic exercise, jogging, tennis, or bouncing when coming down stairs) for two weeks so that the small blood clot that temporarily forms over the biopsy site does not become dislodged.
• Report to your doctor any abdominal pain, or pain that radiates down into the groin. However, mild aching and discomfort in the loin area (due to irritation of the back muscles) is typical and not cause for concern.

Occasionally the kidney tissue sample obtained is not adequate for diagnosis, and the biopsy must be repeated.

The biopsy sample will be examined by a pathologist and reviewed by your nephrologist.

It provides the most accurate assessment of abnormalities in kidney tissue.

It's an invasive procedure accompanied by a risk of moderate to severe kidney damage.

If your kidney biopsy shows a treatable problem, you may be offered therapy with specific drugs. Otherwise, you may receive treatment for risk factors, such as high blood pressure or high blood cholesterol, that may have an impact on your kidneys.