What is a Kidney Biopsy?
A kidney biopsy involves taking one or more tiny pieces (samples) of your kidney to look at with special microscopes. The microscopes make it possible to see the samples in greater detail.
The biopsy sample may be taken in one of two ways:
- Percutaneous (through the skin) biopsy: a needle placed through the skin that lies over the kidney and guided to the right place in the kidney, usually with the help of ultrasound.
- Open biopsy: the kidney sample is taken directly from the kidney during surgery. The kidney sample is then sent to a doctor (pathologist) who looks at it with microscopes. He or she will check for any signs of disease.
What are the reasons for doing a kidney biopsy?
Some kidney problems can often be found with blood and urine tests, a sonogram (an image made by ultrasound) or other special x-rays, and a physical exam rather than a biopsy. But in some patients with certain types of kidney disease, and those with a kidney transplant that is not working well, a correct diagnosis can only be made with a kidney biopsy.
Specific reasons to do a kidney biopsy include:
- Blood in the urine (hematuria) or protein in the urine (proteinuria)
- Abnormal blood test results
- Acute or chronic kidney disease with no clear cause
- Nephrotic syndrome and glomerular disease (which happens when the filtering units of the kidney are damaged)
A kidney biopsy may also help to find:
- If a disease is getting better with treatment or if it is getting worse. It may also show a problem that cannot be cured, but can be slowed down by other therapy.
- How much permanent damage has happened in the kidney.
- Why a transplanted kidney is not working well and helps your doctor decide on further treatment.
- A kidney tumor.
- Other unusual or special conditions.
- If a certain treatment is hurting your kidneys
Your healthcare provider should explain the reasons for the kidney biopsy. You should know why it is necessary, the benefits, and any risks. You will be asked to sign a consent (permission) form to make sure you are aware of any risks. Be sure you understand the risks before you sign the consent form. You may want to write down a list of questions about the biopsy.
What are the possible risks of kidney biopsy?
The risks of kidney biopsy are very small, but they should be discussed with your healthcare provider. As in other medical and surgical procedures, certain complications may happen even though every effort is taken to prevent them. A blood transfusion may be needed if serious bleeding occurs. Rarely, surgery may be needed to fix a blood vessel that is damaged during the procedure.
How should you prepare for the biopsy?
For two weeks before the biopsy, you should not take aspirin, over-the-counter pain medicines such as aspirin, ibuprofen, naproxen, Advil®, Nuprin®, or other medicines that may cause thinning of the blood. These medicines can change the way the blood clots and raise the risk of bleeding. For the same reason, you should stop taking some supplements such as fish oil. Blood and urine samples are usually taken before the kidney biopsy to make sure you do not have an infection or other condition. Your doctor may also want you to change other medications before the biopsy. You may be told to not eat or drink for eight hours before the procedure.