Blood tests and venepuncture factsheet

Introduction

When your child has a blood test, a doctor or nurse uses a needle to take a small amount of blood from their vein. This is called venepuncture.

Blood tests are sent to a lab for testing by a doctor called a pathologist. Pathologists test blood to look for:

  • different diseases
  • infections
  • check levels of things like vitamins and hormones.

Some illnesses and conditions can only be checked by a blood test. 

 Before the test

Your child's doctor or nurse will explain why the test is needed and what it is checking for. 

It is normal for children not to like needles. You can ask for special creams or other devices that reduce pain from the needle. 

This cream can take about 30 minutes to work, so it can only be used if the blood test is not urgent. Creams and other devices for blood tests may not be available at your local clinic, so it's important to call ahead to check.

Parents and carers can stay with their children to support and distract them while blood is being taken. 

 During the test

Generally, the steps of taking a blood sample using venepuncture are:

  1. you or your child, depending on their age, will be asked to check the details on some stickers that will be used to label the blood samples
  2. an elastic belt called a tourniquet is put around your child’s arm and is pulled tight to help show where a good vein is 
  3. the skin over the vein is cleaned with a small alcohol swab
  4. a needle is put into the vein, and blood is taken quickly into several vials.

Once the blood is collected, the needle is removed, and a cotton ball is pressed on top to stop the blood from flowing.

Your child needs to sit still while their blood is being taken. A nurse may need to hold your child’s arm to keep the needle from moving or coming out. This is to keep your child safe and avoid having to retake blood. 

A second sample might need to be taken if: 

  • a vein can't be found
  • not enough blood was taken
  • your child moves, and the needle comes out of the vein. 

Veins can be challenging to find in small children and those who are very young or chubby, like babies and toddlers. 

 After the procedure

There can be some soreness and bruising after the venepuncture, depending on how easy the vein was to find and whether there was any movement. This should go away quickly. 

Last updated Wednesday 12th June 2024

Disclaimer

This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.


© Sydney Children’s Hospitals Network 2024