Your child will be taken to the room where the kidney biopsy will take place. It normally takes about one hour.

If your child is having local anaesthetic, you can usually stay with him or her during the procedure.

Sedation and anaesthesia

It is important that your child is as comfortable and pain-free as possible during the biopsy. Your hospital will use sedation and/or anaesthesia – your doctor will speak with you about the best options for your child.


Sedation is the use of medicines (sedatives) to go into a sleep-like state.

  • This medicine may be injected into a blood vessel using a cannula, a plastic tube.
  • This medicine may also be breathed in during the procedure, using a hand-held mouth piece. After the biopsy, your child can breathe air normally and the gas quickly stops working. One type is a mixture of nitrous oxide and oxygen, the same as “gas and air” that some women use during childbirth.


Anaesthesia is the use of medicines (anaesthetics) to avoid feeling pain. There are two types of anaesthesia.

  • Local anaesthetic: this medicine is put on a particular area of the body to avoid feeling pain there. In a kidney biopsy, the medicine is injected into the skin where the cut will be made for the needle, and into the muscle under the skin and over the kidney. This is so your child does not feel pain when the needle is pushed down towards the kidney.
  • General anaesthetic: This medicine makes your child go to sleep so they do not feel pain anywhere in their body, as well as making sure they keep still during the biopsy. A general anaesthetic may be given as a gas that your child will breathe in, or it may be injected into a blood vessel. 

About the procedure

The doctor uses an ultrasound scanner to help find the right part of the kidney. This shows pictures of the inside of the body. It is similar to the scan that many women have when they are pregnant. 

The doctor makes a small cut in the skin. He or she inserts a needle with a hollow centre through the cut and into the kidney and removes one or more small samples of kidney.

  • If your child is having a biopsy of their own kidney, he or she lies on their tummy or side (because the kidneys sit near the back of the body). If the biopsy is on a transplanted kidney, he or she will lay on their back (because a transplanted kidney is usually near the front of the body).
  • The skin where the biopsy needle will be inserted is cleaned with an antiseptic, which makes sure the area is completely clean.
  • The doctor makes a very small cut into the skin – about 2-3 mm wide.
  • The doctor then inserts the biopsy needle through the cut. If your child is awake, he or she may be asked to take a breath and hold it for a few seconds. Your child should not feel any pain, though they may feel some pressure. He or she may also hear a sharp, clicking noise.
  • The biopsy needle has a hollow centre, and when it is removed, it brings a very small piece of kidney with it. This will be about 1-2 cm long.
  • Your doctor may need to do this a few times to get a good sample.
  • When the doctor has finished, the biopsy site is covered with a dressing. It often oozes a little after the biopsy, but this will stop when pressure is applied to the site.