A renal biopsy is the removal of a small piece of kidney tissue for examination.

Kidney biopsy; Biopsy - kidney

There are many ways to do a kidney biopsy. They include:

• Ultrasound-guided kidney biopsy
• CT-guided kidney biopsy
• Surgical biopsy

The most common kidney biopsy uses ultrasound to guide the doctor to the proper area in your kidney. The biopsy is done in the hospital. Your doctor will go over the procedure, benefits, and risks in great detail.

• You will lie face down for at least 20 - 30 minutes.
• A towel may be placed under your belly area so you stay in the correct position.
• A numbing medicine (anesthetic) is injected under the skin near the kidney area.
• The health care provider makes a tiny cut in the skin. The doctor uses ultrasound images to find the proper location.
• A biopsy needle goes through the skin to the surface of the kidney.You will be asked to take and hold a deep breath as the needle goes into the kidney.

If the health care provider is not using ultrasound guidance, you may be asked to take deep breaths to verify the needle is in place.

• The doctor removes the biopsy needle. Pressure is applied to the biopsy site to stop the bleeding.
• The needle may need to be inserted again (possibly several times) before enough tissue is collected.
• After the procedure, a bandage is applied to the biopsy site.

You will need to stay in bed for 6 - 8 hours after the procedure and will remain in the hospital for at least 12 hours. The health care team will give you pain medicines and fluids by mouth or a vein. Your urine will be checked for excessive bleeding. (A little bleeding usually occurs.) Blood counts and vital signs are monitored.

Kidney biopsies may also be done using CT scan guidance.

In some cases, your doctor may recommend a surgical biopsy. Although surgical biopsies have traditionally required a 3- to 5-inch cut, they can often be done laparoscopically, which uses smaller surgical cuts. Surgical biopsies involve a longer recovery than a simpler needle biopsy.

Tell your health care team if you are pregnant or if you have any drug allergies or bleeding problems. Make sure the health care team knows what medications you are taking.

You may be told to avoid foods or fluids before the test.

The amount of pain during and after the procedure depends on the patient.

Numbing medicine is used, so there is usually minimal pain during the procedure. The numbing medicine may burn or sting when first injected.

After the procedure, the area may feel tender or sore for a few days.

You may see bright, red blood in the urine the first 24 hours after the test. If the bleeding lasts longer, tell your health care provider.

Your doctor may order a kidney biopsy if you have an unexplained drop in kidney function, persistent blood in the urine, or protein in the urine. The test is sometimes used to evaluate a transplanted kidney.

A normal value is when the kidney tissue shows normal structure.

Talk to your doctor about the meaning of your specific test results.

An abnormal result means there are changes in the kidney tissue. This may be due to:

• Infection
• Poor blood flow through the kidney
• Connective tissue diseases such as systemic lupus erythematosus
• Other diseases that may be affecting the kidney, such as a kidney
• Kidney transplant rejection, if you had a transplant

Abnormal results may also be due to:

• Acute nephritic syndrome
• Acute tubular necrosis
• Alport syndrome
• Atheroembolic renal disease
• Chronic glomerulonephritis
• Complicated urinary tract infection
• Diabetic nephropathy
• Focal segmental glomerulosclerosis
• Goodpasture syndrome
• IgA nephropathy (Berger's disease)
• Interstitial nephritis
• Lupus nephritis
• Medullary cystic kidney disease
• Membranoproliferative GN I
• Membranoproliferative GN II
• Membranous nephropathy
• Minimal change disease
• Nephrotic syndrome
• Post-streptococcal GN
• Rapidly progressive glomerulonephritis

This list is not inclusive.

Risks include:

• Bleeding from the kidney (in rare cases, may require a blood transfusion)
• Bleeding into the muscle, which might cause soreness
• Infection (small risk)

Avoid strenuous activities and lifting heavy objects for 2 weeks after the test. Sometimes a repeat biopsy is needed.

Maya ID, Allon M, Saddekni S, Warnock DG. Interventional nephrology. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 28.

Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 116.