Renal (kidney) biopsy

Renal (kidney) biopsy

A renal biopsy is a test that is done to look directly at your child's kidney.

What is a renal biopsy?

A renal biopsy is a test that is done to look directly at your child's kidney. A very small piece of kidney tissue is taken out. This is done by doctors from the x-ray department using an ultrasound machine that helps them guide the needle. It is usually done under a general anaesthetic so your child will be asleep while it is being done. There is no cut as the test is done with a needle. Each kidney contains hundreds of thousands of little filters and only about 20 to 30 are taken.

Why is my child having a renal biopsy?

A renal biopsy can provide lots of detailed information about what is going on in the kidneys. Although blood and urine tests provide a lot of useful information on the function of the kidneys, a renal biopsy allows a kidney specialist to look at the structure of the filters of the kidney. This extra information helps your doctors to decide what is causing the kidney problem and on the best treatments. Kidney biopsy is only done when the patient history, blood, urine and ultrasound information is not enough to tell the doctors what is causing the kidney problem.

What happens before the procedure?

Before having a biopsy your child needs to have a scan to see if they have two kidneys in the normal place. They will also need to have blood tests to make sure that their blood clots normally. These will be organised by your paediatrican or the x-ray department that is doing the biopsy.

As the biopsy is done under a general anaesthestic your child will be asked not to eat and drink from early in the morning on the day of the test.

What happens during the procedure?

Your child is usually admitted to the children's ward or possibly to a short or day stay ward. The biopsy is done under a general anaesthestic so your child will be asleep. The biopsy itself only takes a few minutes.

What happens after the procedure?

After the biopsy your child will go to recovery to wake up and then go back to the children's ward or short / day stay ward. Your child will have a small plaster on their back and this can be removed after a couple of hours. To reduce the chance of bleeding or bruising inside the kidney, staff will ask that your child lies on a bed for five to six hours after the test. Your child can eat and drink normally afterwards. If they are sore they can have paracetamol or another painkiller. After a few hours, if everyone is happy then you can take your child home.

Are there likely to be any complications?

Complications are very rare. They include the possibility of some bleeding afterwards, and pain. This is because there are thousands of little blood vessels inside the kidney and the test can cause some bruising inside the kidney. This should settle very quickly.

How can I prepare my child?

You may find some of the suggestions in Helping your child manage their health care treatment / procedure useful.

How do I find out the results?

Several different tests will be done on the piece of kidney. Some of the results come back in days and some can take longer. Sometimes the biopsy needs to be sent to an overseas specialist to look at. Your paediatrician will contact you when the results are available.

What can my child expect after returning home?

Your child might feel sore for a couple of days afterwards and giving paracetamol regularly can help with this. (You must follow the dosage instructions on the bottle. It is dangerous to give more than the recommended dose). They should not receive ibuprofen as this can cause problems within the kidney.

Your child can go back to school after a couple of days. They should avoid playing sports for a week afterwards.

Call your paediatrician or the children's ward for advice if: 

  • your child has pain that's getting worse
  • your child's wee (urine) is getting red, or coke-coloured
  • they have a fever

The Paediatric Society of New Zealand acknowledge the cooperation of Starship Children's Health, Auckland District Health Board.

This content has been adapted from:

  • Renal Services. Starship Children's Health. Auckland District Health Board. 2009. Having a renal biopsy: Information for children and families.

This page last reviewed 25 June 2015.
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