4 things to know about kidney biopsies

At MD Anderson, our dedicated interventional radiologists perform around 500 kidney biopsies a year. Nearly all of them are guided by advanced imaging technology. This approach allows us to pinpoint the most effective locations to extract tissue samples from, ensuring both accuracy and precision.

But what insights can a kidney biopsy provide about this vital organ? Why would your doctor recommend one? And, most importantly, will it be painful?

Understanding a kidney biopsy

A kidney biopsy is a minimally invasive procedure in which a doctor uses a small needle to collect tissue samples from the kidney. These samples may be taken from a kidney mass or from the organ itself. The samples are then sent to a pathologist for detailed analysis under a microscope.

Doctors may order a kidney biopsy for a variety of reasons. Perhaps a radiologist noticed a kidney mass during imaging for unrelated issues. Or, lab tests revealed blood in your urine or signs of kidney dysfunction, particularly after a kidney transplant. A biopsy could also be called for if your kidneys are affected by autoimmune disease, immunotherapy, or some other form of cancer treatment. 

Interestingly, up to 60% of small kidney masses are now discovered incidentally, during scans performed for other reasons. At MD Anderson, they are often discovered in patients being assessed for cancers unrelated to kidney cancer.

What can a kidney biopsy reveal?

If a biopsy targets a specific mass, it can determine whether it is malignant (cancerous) or benign (non-cancerous). It can also identify the type of cancer, such as renal cell carcinoma, the most prevalent form of kidney cancer. This is crucial for appropriate treatment planning.

When a pathologist examines biopsy samples, a variety of other conditions may be uncovered as well. 

Examples include:

• Glomerular diseases: involve damage to the kidney’s filtering units (glomeruli) that clean the blood, and include inflammation (glomerulonephritis) and thickening (glomerulosclerosis)
• Tubular and interstitial diseases: affect the kidney tubules (acute tubular necrosis) and the surrounding tissues; could be related to infections, toxins, or autoimmune diseases
• Transplant rejection: if the body is rejecting a transplanted organ
• Fibrosis: scarring of the kidney tissue

Regardless of the findings, kidney biopsies play a crucial role in informing doctors about their patients’ conditions, guiding more effective treatment decisions.

Blueprint of a kidney biopsy 

The actual extraction of kidney cells typically takes just 10-20 minutes. But the complete procedure, including patient preparation, sedation, and the acquisition of samples, spans about an hour. 

The majority of patients tolerate the procedure very well, and any discomfort can be controlled with local anesthesia and IV sedation.

Though any procedure involving a major organ carries inherent risks, kidney biopsies are considered minimally invasive and are performed in an outpatient setting. Patients can usually return to work and resume normal activities within 24 hours.

Kidney biopsy risks

The kidneys are highly vascular organs, meaning they contain many blood vessels. So, one of the main risks of a kidney biopsy is bleeding.

Some patients develop minor bleeding after the procedure, which can be visible in their urine. Fortunately, this is typically manageable without additional treatment. In rare cases, when bleeding requires intervention, procedures like embolization can effectively address the issue.

We have some of the most experienced specialists in the field performing kidney biopsies here at MD Anderson. That makes them a safe option for patients seeking clarity about their kidney health.

Mohamed Abdelsalam, M.D., is an interventional radiologist specializing in minimally invasive, image-guided kidney interventions.  

Request an appointment at MD Anderson online or call 1-888-568-0329.