Renal Biopsy

Renal Biopsy

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


Key points to remember about renal biopsy

  • a renal biopsy is a test to look directly at your child's kidney
  • doctors from the x-ray department will take out a very small piece of kidney tissue
  • renal biopsies usually happen under a general anaesthetic so your child will be asleep

What is a renal biopsy?

A renal biopsy is a test to look directly at your child's kidney. Doctors from the x-ray department will take out a very small piece of kidney tissue. They use an ultrasound machine that helps them guide the needle. Renal biopsies usually happen under a general anaesthetic so your child will be asleep. There is no cut as doctors use a needle to do the test. Each kidney contains hundreds of thousands of little filters and doctors remove only about 20 to 30.

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.

Doctors will only do a Kidney biopsy when the patient history, blood, urine and ultrasound information is not enough to explain what is causing the kidney problem.

What happens before a renal biopsy?

Before having a biopsy your child needs to have a scan to see if they have 2 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 happens under a general anaesthetic, the healthcare team will ask your child not to eat and drink from early in the morning on the day of the test.​

What happens during a renal biopsy?

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 a renal biopsy?

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 5 to 6 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 of a renal biopsy?

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 for a renal biopsy?

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

How do I find out the results of my child's renal biopsy?

Laboratory staff will do several different tests on the piece of kidney. Some of the results come back in days and some can take longer. Your paediatrician will contact you when the results are available.

What can my child expect after returning home following a renal biopsy?

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 in their loin or between their ribs and hip that's getting worse
  • your child's wee (urine) becomes 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 26 June 2018.

Call Healthline on 0800 611 116 any time of the day or night for free health advice when you need it