Your urologist may recommend that you have a kidney biopsy. A biopsy involves collecting small pieces of tissue which are sent to a lab for analysis and provides information about the best course of treatment. A pathologist will examine the kidney tissue samples for unusual deposits, scarring, or infection. If you have progressive kidney failure, the test may show how quickly the disease is advancing.

A kidney biopsy may be recommended for:

  • Hematuria, which is blood in the urine.
  • Proteinuria, which is excessive protein in the urine.
  • Impaired kidney function, which causes excessive waste products in the blood.
  • A transplanted kidney that isn't working properly.

Before the Test

  • Tell your nurse or doctor about any medications you are taking or any allergies you may have.
  • Do not take aspirin or other blood-thinning medicines for 1 to 2 weeks before the procedure.
  • Your urologist will advise you on food and fluid intake before the test.
  • Shortly before the biopsy, blood and urine samples will be taken to make sure you don't have a condition that would make doing a biopsy risky.

During the Test

  • The patient is fully awake with light sedation.
  • A local anesthetic is given before the needle is inserted.
  • Patients lie on their stomachs to position the kidneys near the surface of their backs.
  • The doctor marks the entry site, cleans the area, and injects a local painkiller.
  • For a biopsy using a needle inserted through the skin, the doctor uses a locating needle and x-ray or ultrasound equipment to find the kidney.
  • You may be asked to hold your breath as your doctor uses a spring-loaded instrument to insert the biopsy needle and collect the tissue. It only takes about 30 seconds or a little longer for each insertion.
  • The spring-loaded instrument makes a sharp clicking noise.
  • The doctor may need to insert the needle three or four times to collect the needed samples.
  • The entire procedure usually takes about an hour,

After the Test

  • You'll lie on your back in the hospital for a few hours.
  • Patients who have a transplanted kidney lie on their stomachs.
  • The staff will continue to monitor your vital signs.
  • Most patients leave the hospital the same day.
  • You may notice some blood in your urine for 24 hours after the test.
  • Results are usually ready in a few days. Your physician will discuss the results with you.