A kidney biopsy is a medical procedure where a small piece of kidney tissue is removed to examine under a microscope. This is done to check for any signs of damage or disease that may be affecting the kidney’s function or causing other health problems. A kidney biopsy can provide important information about kidney function, helping nephrologists (doctors specializing in kidney health) diagnose and treat kidney conditions. Kidney biopsies are sometimes requested to diagnose suspected kidney issues, such as IgA Nephropathy (IgAN), or to develop treatment plans based on the kidney’s current condition. Additionally, kidney biopsies can help determine how quickly a kidney is deteriorating or improving, and monitor the health of a transplanted kidney.
In the US, nearly two million kidney biopsies are performed each year at a rate of 175 procedures per million population. Kidney biopsies can reveal important information about kidney function and inform nephrologists about the possible cause of symptoms that brought the patient in for a visit in the first place. Nephrologists also study how the kidneys affect other parts of your body, such as the immune and cardiovascular systems.
Your doctor may recommend a kidney biopsy to:
- Diagnose kidney issues that cannot otherwise be identified through other means, such as an IgAN diagnosis
- Develop treatment plans based on the kidney’s current condition
- Determine how quickly a kidney is deteriorating or improving
- Monitor the health of a transplanted kidney
After the procedure, most patients can leave the hospital the same day or around 12 to 24 hours after the procedure. It’s important to rest for another day or two and to ask your care team about any activity restrictions, such as work, heavy lifting, and strenuous exercise. The area where the biopsy was performed may be tender for a few days, but this discomfort is typically mild and easily managed.
What Will A Kidney Biopsy Reveal
Many patients and families who encounter a renal biopsy wonder, “What will a kidney biopsy reveal?” Generally, a kidney biopsy will reveal scarring, inflammation, and protein deposits that may not be visible in other diagnostic tests, such as ultrasounds, blood, and urine tests. Abnormal biopsy results may indicate unexpected scarring, inflammation, or protein deposits that shouldn’t be there.
An abnormal biopsy result might reveal:
- Poor blood flow through the kidney
- Connective tissue disease or other diseases that affect the kidney, such as diabetes
- Kidney rejection, in the case of a transplanted kidney
After the biopsy has been performed, It may take between three to five days for the results to be available. This is because a specially trained pathologist must read and interpret the biopsy.
Several symptoms may indicate a need for a kidney biopsy. This will be determined by your nephrologist, but generally, these symptoms include:
- Blood in the urine
- Protein in the urine
- Sudden onset kidney disease with no clear cause
- Nephrotic syndrome and glomerular disease, which happen when the parts of the kidney that filter out toxins are damaged
The first signs of kidney issues usually include blood and protein in the urine, swelling in your hands and feet, and high blood pressure. Kidney biopsies are ordered to confirm suspicions that these symptoms are directly related to the kidney.
The scarring, inflammation, and protein deposits that may be revealed by kidney biopsies can help nephrologists determine:
- How quickly kidney disease is progressing
- The extent of the damage from existing kidney disease or other problems that impact the kidney
- How the current treatment plan for kidney disease is working
The results of a kidney biopsy can be used to diagnose and formulate a treatment plan with the patient if the results call for it.
Kidney Biopsy Preparation
Preparing for a kidney biopsy is an essential step to ensure the procedure goes smoothly and effectively. Before your biopsy, it is important to meet with your physician to discuss the procedure, what to expect, and how to prepare. Be sure to bring a list of all the medications you take, including over-the-counter drugs, vitamins, herbal supplements, or other home remedies.
To minimize the risk of bleeding, it is crucial to stop taking certain medications before the biopsy. These typically include blood thinning medications such as warfarin, rivaroxaban, dabigatran, or enoxaparin, as well as ibuprofen and other nonsteroidal anti-inflammatory drugs.
Your care team will let you know when these medications should be stopped and when they can be continued again. In general, it is recommended to stop these medications at least seven days before the biopsy, although some medical professionals may suggest stopping them up to fourteen days before the procedure. Your care team will also provide instructions on when it is safe to resume taking these medications, typically seven to fourteen days after the procedure.
It is also important not to eat or drink for up to eight hours before the procedure to ensure that your stomach is empty during the procedure. Kidney biopsy anesthesia is usually local, which means you will be receiving numbing medication to the area where the biopsy will be done. This will help to ensure that you do not feel any pain during the procedure. You will be positioned lying down on an exam table, and the biopsy location will depend on whether the kidney is transplanted or not.
If the biopsy is being performed on a native kidney (a kidney in its original position), you will be positioned on your stomach with a pillow placed underneath your rib cage to help expose the kidney. If the biopsy is being performed on a transplanted kidney, you will lie on your back. The doctor will use an ultrasound probe to identify where to insert the needle. The doctor will then mark the skin, disinfect the area, and apply a local anesthetic. They will then make a very small incision where the needle will go in and use the ultrasound probe to guide the needle into the kidney. You may feel a small pinch, pop, or pressure as the sample is collected. The entire procedure, from start to finish, typically lasts about an hour.
After the sample has been collected, the doctor will remove the needle and a bandage over the incision site. It’s common to feel a little soreness or discomfort at the biopsy site, but this should improve in a few days. It’s essential to follow your doctor's instructions regarding recovery, which may include resting for a short time and avoiding strenuous activities for a few days.
While complications are rare, it’s essential to monitor your symptoms after the biopsy. Your doctor will provide you with detailed instructions on what to look out for and when to seek medical attention. For example, if you experience significant pain, swelling, or bleeding from the biopsy site, or if you develop a fever or chills, contact your doctor immediately. By following these guidelines and working closely with your healthcare team, you can minimize your risk of complications and ensure a successful biopsy.
Kidney Biopsy Recovery
Kidney biopsies are one of the least invasive and most confident methods to diagnose kidney disease and other problems that impact the kidney. Recovery from a kidney biopsy is usually straightforward. Although many patients can leave the hospital the same day of the procedure, it is not uncommon to stay overnight or 12 to 24 hours after the procedure. This is to monitor any issues that may come up such as minor bleeding or tenderness in the area.
It is normal to experience some slight abdominal pain and tenderness for a few days after the procedure. Your care team will inform you of specific restrictions, such as no heavy lifting, driving, or showering for 24 to 48 hours after the biopsy. Specific recovery recommendations may be unique to each case, but, general kidney biopsy aftercare instructions include:
- Resting for 24 to 48 hours after the procedure, only getting up to use the bathroom
- Not driving for 24 to 48 hours after the procedure.
- Avoid showering for 24 hours after the biopsy. If your provider allows, you may gently sponge clean yourself. When showering is possible, do not scrub the site. Gently wash the area and pat it dry.
- Not removing the bandage until 24 to 48 hours after the biopsy.
- Avoid lifting anything heavier than 10 pounds for up to four days after the procedure.
- Consult your doctor for a return to work date. Be sure to make your physician aware if your job involves heavy lifting.
- Check with your doctor before taking any medications that affect blood clotting, such as aspirin or prescription blood thinners.
While it is common to experience some slight tenderness in the days following a biopsy and have some minor bleeding on the biopsy bandage, severe pain after a kidney biopsy is not normal. If you experience severe pain or any of these other symptoms after your biopsy, you should contact your healthcare provider right away:
- Bloody urine or feeling unable to urinate
- Exhaustion or extreme fatigue
- Lightheadedness or dizziness
- Struggling to catch your breath
- Sudden chest pain
- A fever of 100.4 Fahrenheit or higher
- Increasing redness, pain, or swelling at the biopsy site
- Openage, draining, or bleeding from the biopsy site
The rate of serious complications in the case of a kidney biopsy is very low - between 1% and 7%. Your doctor should inform you of the results of your biopsy at your follow-up appointment, usually received within 3 to 5 days of the procedure. However, a partial report may be available in less than 24 hours. Kidney biopsy results can be used to create a treatment plan for the symptoms that resulted in the biopsy in the first place or to stabilize a pre-existing treatment plan. Working with your doctor to create a care plan for recovery as you await the results of your biopsy may be useful in ensuring a smooth recovery.