A kidney biopsy is a procedure where a tiny piece (sample) of a kidney is removed from the body. This sample is examined under microscopes to find out more about the kidney’s health.

About the kidneys and urinary system

The kidneys are part of the urinary system, which gets rid of things that the body no longer needs, so that we can grow and stay healthy.

The kidneys are bean-shaped organs. They filter blood and remove extra water, salt and waste in urine (wee). Most of us have two kidneys. They are at the back on either side of our spine (backbone), near the bottom edge of our ribs.

The two ureters are long tubes that carry urine from the kidneys to the bladder.

The bladder is a bag that stores urine until we are ready to urinate (wee). It sits low down in the pelvis.

The urethra is a tube that carries urine from the bladder to the outside of the body. 

Why does my child need a biopsy?

Your child’s specialist doctor – a paediatric nephrologist – may recommend a kidney biopsy.

Diagnose a condition

A kidney biopsy can help your doctor diagnose (identify) a condition, so that the most appropriate treatment can be started. It may be done when other tests have not been able to give enough information.

Some of the problems that might need a kidney biopsy include:

  • blood in their urine (wee) that keeps coming back (haematuria)
  • large amounts of protein in their urine (proteinuria), as in nephrotic syndrome
  • poor kidney function (how well kidney is working), which can quickly become worse without a known cause.

Find out how well treatment is working

If your child is being treated for a kidney condition, a kidney biopsy can help find out how well their kidneys are responding to treatment.

Find out more about a transplanted kidney

If your child has had a kidney transplant, he or she may need a kidney biopsy, especially if blood tests indicate the kidney may not be working as well as previously.


Occasionally, a kidney biopsy needs to be done urgently while a child is in hospital. This is to find out information about the kidney if it has suddenly stopped working as well as it should.

More information about kidney biopsies

  • Preparing for a kidney biopsy

  • Kidney biopsy procedure

  • After a kidney biopsy