Paediatric Blood Tests

If your child is requested to undergo a blood test, the following information will help answer some common queries that you may have.


Preparing for a Blood Test

Preparing your child for what happens during blood taking is an important part of the process.  Not knowing why an injection or blood test is needed and what will happen can be frightening for some children.  Explain as best as you can how and why the doctors think an injection or blood test will make your child better or check their treatment.  Use play to talk about the whole process of taking a blood test, perhaps using a teddy or doll as the ‘patient’.  You could put a dab of cream on their teddy’s hand to explain the anaesthetic cream, use a ribbon as a tourniquet and talk about the importance of keeping their hand and arm still. 


When and how you tell your child about the blood test will vary depending on their age and understanding.  You know your child best, so tailor the information to their needs and level of understanding, but make sure that it is truthful.  This is a good way to ease anxiety.


It is not always helpful to tell children to ‘be brave’ when having a blood test.  We do not mind children shouting or crying during a procedure although, if you think they will struggle to cope, it would be helpful if you could warn us beforehand.


Discuss what you will do after the procedure with your child.  It can be a simple treat, such as a trip to the park or to the shop to buy a drink.  This helps let your child feel they have had some choice and also have something nice to focus on while the procedure is taking place.


If watching the procedure is something that you will find very distressing, please ask somebody else to accompany your child for the treatment while you wait in the waiting room.


What Happens During a Blood Test?

A local anaesthetic cream (sometimes referred to as “Magic Cream”) will be applied to the back of your child’s hands or the inside of their elbow by the nurse, so the needle does not hurt as much when it is inserted, although it does not completely remove the feeling.  This is suitable for children over one month of age. 


Some children are told that the cream is ‘magic’ so they will not be able to feel anything.  This is not entirely true.  We suggest that you say that they might feel some pressure, pushing or holding – but do not promise that it will not hurt.

More than one area will have cream on to enable the nurse to choose the best site.  Cling film is then used to wrap the arm and/or hand, acting like a bandage to keep the cream in place.  We do not use plasters as they hurt when removed and cloth bandages will absorb the cream rather than the skin.  It takes 30 minutes for the cream to be fully effective, so we suggest that you bring items to keep your child occupied while you wait, such as toys, books or a tablet device.


Once the cream has taken effect, the nurse will position your child on your lap, or if your child chooses they can sit on their own on the couch with you sitting/standing beside them to provide reassurance and comfort.  The details on the request form will be checked with you to ensure we have the right information.  The cream will be removed and the nurse will choose the most appropriate site, either an arm or hand.  You will be instructed what to do, how to hold your child and encouraged to distract them – looking the opposite way to where the blood test is being performed.  The idea is that by taking your child’s mind off what is happening, the pain and fear associated with it will reduce.  Any activity that takes a child’s mind away from what is happening is worth trying.  Some things that may be useful include:


  • Books, especially “Where’s Wally?” type books
  • Noisy toys, such as rainmaker for the infants
  • Bubbles
  • Playing ‘I Spy’ or noticing things in the room
  • Talking about familiar people, pets, places or a happy memory
  • Singing
  • Deep breathing or the use of electronic devices as a distraction tool


Cold spray (ethyl chloride) is sometimes used to minimise any pain your child feels.  It is a vapo-coolant and we spray a thin film onto the skin just before the blood test.  This makes the skin cold, and less sensitive as it evaporates.  This works within seconds, but wears off within minutes.  It can be useful for children who are sensitive to numbing creams.


Once the site is cleaned a tight band, known as a tourniquet will be placed above the area where the blood test will occur; this makes the vein fill up with blood and makes it easier for the blood sample to be taken.  A needle is then inserted into the vein which is connected to a syringe and the blood taken out.  It usually takes less than a minute to collect the required amount of blood, after which the needle is removed.  Pressure is applied to the small wound with cotton wool for a few minutes to stop the bleeding and prevent bruising. While the nurse puts the blood into bottles and labels them, your child will be encouraged to choose a bravery certificate and sticker to help them feel they have achieved the goal of having blood taken.


It is important that you remain calm and positive throughout the blood test to help your child feel the same.



Written consent is not required for a blood test.  We will ensure you understand the reason for the blood test, which will have been explained by your doctor and check the details on the request form, confirming your child’s full name and date of birth.  This will be taken as verbal consent.  We also use implied consent where the action of attending the appointment and holding out your child’s hand or arm is taken as consent for the blood test to happen.


Different Blood Samples

Blood can be tested for many different things.  Your doctor will write on the form which tests they want us to take. Different blood bottles are used for different tests – this is why you may see your blood added to bottles of different sizes and colours.



Unless you are told differently by your doctor, the results from your child’s blood test will go back to them.  This may take up to one week but may be longer depending on the reason the blood test is being performed.  They should contact you once the results are available.

Why One Hatfield

  • Modern purpose-built hospital opened in December 2017
  • Fast access to diagnostics including MRI, X-ray and Ultrasound
  • Private, spacious, en-suite rooms
  • Specialist physiotherapy and nursing teams
  • Little or no waiting time
  • ‘Ultra clean air’ theatres
  • Freshly prepared food
  • Calm, dignified experience

Contact us and find out more

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