Kidney biopsy is a procedure that removes a small piece of the kidney. The tissue is then looked at under a microscope to help your kidney doctor figure out the cause of the kidney disease. Results take about 7 days.

Reasons for a Kidney Biopsy

A kidney biopsy helps figure out the cause of kidney disease, how much scaring is present and if it can be treated. You may need a kidney biopsy if:

  • You have protein in the urine,

  • You have blood in the urine, or

  • Your kidneys are not removing toxins as they should from the blood.

Getting Ready

  • Stop all blood thinners 7 days before biopsy.

  • No NSAIDS such as ibuprofen, naproxen, Motrin, Aleve, aspirin or products that contain aspirin and fish oil for 7 days before the biopsy.

  • Take your blood pressure medicines or other prescription medicines with a small sip of water the day of biopsy.

  • Do not eat anything after midnight on the day of biopsy.


If you have diabetes, please call your doctor to see if you need to adjust your medicine.

Test your blood sugar more often when you are not eating before the procedure. If your blood sugar is less than 70 mg/dl or you have symptoms of low blood sugar, eat some glucose tablets or drink 4 ounces of a clear liquid with sugar. Always recheck your blood sugar level to make sure it stays above 70 mg/dL.

We may still be able to do the procedure unless you need to eat solid food.

If your blood sugar ever gets too high or too low and you can’t bring it back to normal, call your local doctor or diabetes doctor.

Day of the Biopsy

Check-in at Patient Registration two hours before your biopsy. You will then go to Radiology Prep and Recovery. Our doctors will explain what will happen, answer questions, and ask you to sign a consent form.

You will get an IV and have blood tests done. These tests make sure your blood is not too thin and it is safe to do the biopsy.

Your blood pressure will be checked. It should be below 140/90 to do the procedure safely. This is why you need to take your blood pressure medicines as prescribed.

During the Biopsy

You will be awake. You may get medicines to help you relax. You will be taken to Radiology. We will look at your kidneys using ultrasound. You will be lying on your belly or your side and the doctor will mark the area for biopsy.

Local anesthetic (numbing medicine) is used at the site of the biopsy. The doctor will use ultrasound when doing the biopsy to avoid big blood vessels in the kidney.

Doctors will take a small piece of tissue out of the kidney. You may have to hold your breath when the needle is inserted in the kidney. They will repeat several times to get enough tissue sample.

After the Biopsy

After your biopsy, you will return to the prep and recovery area. You must stay in bed for 4 hours after the biopsy. The nurse will check your blood pressure and pulse to make sure they are stable.

You might feel some pain in your back after the local numbing medicine wears off. Pain is mild and does get better within 24 hours after the biopsy. Let your nurse know if you need something to control pain.

You will go home after the recovery time if your blood counts are stable and you are feeling well.

Avoid all blood thinners. Ask your doctor when you can restart blood thinners. You can restart all of your other medicines.

At Home

  • You may eat or drink what you like once you get home. Do not drink alcohol for the first 24 hours.

  • Rest and take it easy for the first 24 hours. Do not lift more than 10 pounds during this time. Resume your normal routine after 24 hours.

  • You may remove the bandage over the site the next morning.

  • You may shower after 24 hours.

Risks of Biopsy

You may have blood in your urine after the biopsy. This is because kidneys get a lot of blood to filter. Rarely the bleeding might be severe and require a blood transfusion. Very rarely you might need a procedure to stop the bleeding.

When to Call

  • You have more than a teaspoon of bleeding at the site

  • You feel dizzy, faint, or light-headed

  • Your pain around the site gets worse rather than better 2-3 days later

  • Severe back pain

  • Trouble passing urine

  • Blood clots or blood in your urine that is getting worse after 2 days

  • Signs of infection:

    • Nausea or vomiting

    • Chills

    • Fever over 100.4°F (38°C)

Who to Call

Kidney Clinic

Monday-Friday, 8:30 am – 5 pm

(608) 270-5656

Evenings and weekends call your local doctor or go to your local emergency room.

If you are a patient receiving care at UnityPoint – Meriter, Swedish American or a health system outside of UW Health, please use the phone numbers provided in your discharge instructions for any questions or concerns.