Children's cancer tests

Children's cancer tests can diagnose cancer or give more information about your child's cancer and their health. 

Why is my child having tests?

Tests are used: 

  • To diagnose cancer. If your GP is concerned about your child's symptoms, they may refer your child to hospital for some of the tests described below. For example, scans, blood tests and possibly a biopsy.
  • To find out more about your child’s cancer – for example, how big it is, if it has spread or if it’s likely to grow quickly. This is called staging cancer.
  • To look at genetic information to see how a cancer might respond to particular treatments. For example, targeted therapies. This is called cytogenetic testing.
  • To check your child’s general health, for example, before surgery.
  • To see how well your child is responding to treatment.

Understanding tests

Knowing what to expect can help you to prepare your child. Ask your medical team about the test. For example:

  • What is it for?
  • How long will it last?
  • Will there be any discomfort?
  • Can my child go straight home afterwards?

Keeping children amused

If you have to wait during the testing period, bringing books, toys, games, a tablet or music can help to pass the time.

Talking to children about tests

  • It’s a good idea to try and prepare your child for what will happen, based on their age and understanding. If it might hurt, it’s best to be open so they know they can trust you. For example, ‘This will hurt, but only for a minute. Will I hold your hand until you feel better?’ 
  • If you are unsure what is involved in some tests, ask the nurses or play specialist to help you prepare your child. 
  • Your child might like to take part in the Beads of Courage programme. For every kind of test or treatment they have, they receive a coloured bead. They can collect these beads to keep track of their cancer journey and show just how brave they are. This programme is run by the play specialists in St John’s paediatric cancer day ward at CHI Crumlin.

Waiting for results

It can take a week or 2 for some test results to come back. You can ask when the test is being done:

  • When do the doctors expect the results back?
  • Will you be given the results over the phone or in person and who will they contact?

It’s natural to want to hear the results as soon as possible. You may feel very anxious while you’re waiting. Talk to your nurses or call our Support Line and ask to talk to our children’s cancer nurse if you have any questions. 

Types of cancer tests

  • Bone scans 
    A test that can show if cancer is present in bones using a radioactive dye. 
  • CT (CAT) scan 
    This special X-ray gives a detailed picture of the tissues inside your body. During the scan, your child will lie on a table which passes through a doughnut-shaped machine. 
  • MIBG scan  
    Usually done in children who have a diagnosis of neuroblastoma. It involves a radioactive substance being injected into the bloodstream and the scan being taken the next day. This will show up any areas of tumour in the body.
  • MRI (magnetic resonance imaging)
    This uses radio waves and a powerful magnet linked to a computer to take detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. 
  • PET scan 
    This scan is normally done in children who have Hodgkin lymphoma. A very small amount of a radioactive substance is injected into the bloodstream, which can show up cancer cells on a scan.
  • Ultrasound scans
    This scan uses sound waves to build up a picture of the tissues inside your body. It is like the scan used for pregnant women. A gel will be spread over the area to be examined. A small device like a microphone is moved back and forth over the area. The scanning device makes sound waves that are changed into a picture on a computer. This test is not painful but your child will need to lie still on a couch. Sometimes your child may need to fast for an ultrasound or to drink beforehand so that their bladder is full for the test.  
  • X-rays
    X-rays allow your doctor to look inside the body and check for any abnormal changes. They can check your child’s health or help with the diagnosis. X‐rays of the affected area may also be taken at various stages throughout your child’s treatment. X‐rays are not painful but your child must keep very still. 

A biopsy is a small sample of cells removed from the body. The sample is examined under a microscope by a doctor called a pathologist to see if it contains cancer cells or to give your doctor information about the type of cancer and how it might grow (the cancer grade). Biopsies are usually done under anaesthetic. Read more about biopsies. 

This test can be done to diagnose, prevent or treat disease. The fluid that surrounds the brain and spinal cord is called cerebrospinal fluid. During the test, some of this fluid is removed by putting a needle into the lower back. The fluid is then examined in a laboratory. It is done under general anaesthetic. Read more about lumbar punctures.

Blood tests can be used to check your child’s health, to diagnose blood cancers, and to check how well your child is responding to treatment. Read more about blood tests.

Blood samples can be used to examine the cancer cells and their genetic material in detail to give more information about the type of cancer, how it might behave and how it might respond to different treatments. For example, immunophenotyping, FISH analysis and other cytogenetic tests. Find out more about tests to examine cells and genes.

A sample of urine may be taken and checked to see how your child is responding to treatment, to look for infection or to see if there are any problems due to treatment. 

  • GFR (glomerular filtration rate)
    This tests check your child’s kidney function. A small amount of radioisotope is injected into your child’s blood. Blood tests will be taken 2 hours after the first injection and then 2 hours later again. The kidneys are checked because it is known that some chemotherapy and certain antibiotics can damage them. If your child has a single lumen Hickman, he/she will need a small tube (cannula) put into their hand to give the dye.
  • Urinalysis
    A test to check the number of white blood cells and red blood cells in the urine (pee). It also tests for protein, bacteria and sugar. Your child’s urine is collected in a sterile bag or container.
  • Urine VMA (vanillylmandelic acid)
    A test referred to as either ‘urine VMA’ or ‘urine catecholamine’. VMA is a chemical found in the urine in raised amounts when a child has neuroblastoma.      

We're here to help

Our range of free services are here for you

CAYA counselling and psychological support services
Free counselling for families affected by childhood cancer.
Transport Service for children, adolescents and young adults
Free transport for children and young adults travelling from Kildare, Meath, Dublin and Wicklow to CHI at Crumlin for treatment.
Care Kits
Families, adolescents and young adults dealing with childhood cancer often find themselves in hospital suddenly or without time to prepare. Our free Care Kit is an overnight bag filled with some essentials that you can have ready to go for when you need it.

Talk to a Cancer Nurse

Support Line

Support Line

Our Cancer Nurses offer confidential advice, support and information for anyone affected by cancer. Call or email supportline@irishcancer.ie. Video calls available. Mon-Fri: 9am-5pm
Support Line

In-hospital support

The Irish Cancer Society's Children’s Cancer Nurse at Children’s Health Ireland at Crumlin Hospital one day per week provides free, confidential advice, support and information to anyone affected by a child’s cancer.
In-hospital support