Understanding Your Kidney Biopsy Procedure

A kidney biopsy procedure is done to take small pieces of kidney tissue and examine it under a microscope to look for disease or damage. The sample is usually taken using a thin needle that is placed through the skin (this is called a percutaneous biopsy); this is the most common way to do a biopsy. The needle is guided to the right place to be able to take the biopsy using ultrasound imaging that gives real-time, moving pictures of the area.

Read on to find out why a kidney biopsy is needed, how to prepare, potential risks, and questions to ask.

Why is a kidney biopsy procedure needed

As of now, a kidney biopsy is the only way to definitively diagnosis IgAN. A kidney biopsy can also give you and your healthcare team important information about:

  • Whether IgAN treatment is working
  • The extent of IgA deposits, scarring or permanent damage to the kidneys, as well as how many of the kidney’s filters (glomeruli) are still working
  • Determine how quickly the disease might progress (prognosis) based on a MEST-C score (see our video for more in-depth information)
  • If and why a transplanted kidney is not working well

Researchers are quickly working on developing an assay that can detect IgAN using information from a standard blood test. But even when it’s available, it won’t give information about possible scarring or the extent of damage in the kidneys.

What to expect

As with anything to your care, it’s important to ask questions, advocate for yourself and know what to expect. Many people get nervous about the procedure because they have heard not-so-great stories or are afraid of needles, but the procedure is generally safe.

A kidney biopsy usually takes less than an hour. It is usually done on an outpatient basis, so you will likely go home the same day. Some people do need to stay in the hospital overnight

Before the kidney biopsy procedure

Talk with your doctor about what to expect. Ask questions and make sure you understand the risks and benefits of kidney biopsy.

You’ll also need to:

  • Stop or avoid any medications that thin the blood and can increase the risk of bleeding. Bring a list of all of the medications you take, including over-the-counter medications, vitamins and supplements to determine which, if any, need to be stopped, when and for how long.
  • Tell your care team if you have a history of bleeding disorders or if are allergic to any medications, anesthesia or latex.
  • Fast for a period of time – that means not eating and drinking anything before the procedure.

The day of the procedure, the team caring for you will review what will happen during the procedure. You will then be asked to sign a consent form, giving them permission to do the kidney biopsy and verifying that you understand the potential risks. Your blood pressure and pulse will be checked before and during the procedure, and your care team will discuss how they will numb the area and sedation. Blood tests will also be done.

Numbing medicine will be used, and you may receive some sedation too so that you are comfortable. Make sure you have a trusted ride home.

During the procedure

A kidney biopsy is a medical procedure where a small sample of kidney tissue is removed for examination under a microscope to diagnose kidney conditions. Typically performed under local anesthesia, a needle is inserted through the skin into the kidney, guided by ultrasound or CT imaging, to collect the tissue sample.

A Kidney Biopsy Procedure helps doctors assess the extent of kidney disease, inflammation, or scarring and aids in determining the most effective treatment plan. While generally safe, a kidney biopsy carries some risks, such as bleeding or infection, and patients are closely monitored afterward to ensure recovery.

After the procedure

You will rest in bed for a while to help to site of the biopsy heal. You may lay on a pressure pad, similar to a bean bag, for a period of time to put pressure on the site of the biopsy to stop the bleeding. This can be uncomfortable.

Your kidney tissue will be sent to a pathologist – a doctor who is specially trained to look at samples under a microscope and help diagnose health problems. They will examine the tissue and look for scarring, infection and other abnormalities. It often takes a number of days, possibly a week to get the full results from your doctor.

Be sure to call your doctor’s office right away if you continue to bleed, have worsening pain or a fever or if you have any concerns. You should avoid heavy lifting and strenuous activity for a period of time.

Potential risks

A kidney biopsy is generally safe and gives important information about your kidneys. But, as with any procedures, there are risks.

These may include:

  • Bleeding – Bleeding is the most common issue after kidney biopsy. Bleeding can occur from the biopsy site itself or in the urine. If you are worried, tell your doctor.
  • Pain – Pain is common where the biopsy was taken, but the discomfort shouldn’t last long. The kidneys are a very pain-sensitive organ, so you may feel sore for a few days.
  • Infection – in rare cases.
  • Others – Accidental puncture or damage to a blood vessel or nearby organ or loss of a kidney,though these are extremely rare.

Questions to ask

It’s always helpful to think about and write down questions for your health care team ahead of time. Here are some questions as a start:

  • Will you, as my nephrologist, or another doctor (usually an interventional radiologist) be doing the procedure?
  • What happens if not enough of a sample is taken to make the diagnosis?
  • How should I prepare for the test?
  • Are there things that will be done to lower the chance to bleeding or pain?
  • Are there any medications I need to stop taking before I get the biopsy done and, if so, how far in advance?
  • Will I receive any sedation? Will I be awake or under general anesthesia?
  • Do I need to limit any activities or heavy lifting? For how long?
  • What should I watch for after going home (for example, blood in the urine for more than a few days after the procedure, not being able to urinate, fever, worsening pain or redness at the biopsy site)?
  • When will I get my results?
  • When should I restart any medications that were stopped?

Be sure to tell your doctor if you think you could be pregnant.

For more information about kidney biopsy, you can view Dr. Hassler’s in-depth video SPARK presentation. He is also a member of our medical advisory board.

Content expert reviewed: July 2023

Understanding Kidney Biopsy Findings and Reports in IgA Nephropathy