Bone marrow test

By looking closely at your child’s bone marrow under a microscope, doctors will be able to find out more about your child’s blood cells.

In particular, they will look at the number and type of cells that make-up the blood, such as red or white blood cells, and platelets.

Your child’s doctor will explain in more detail why they think your child needs this test.

Hear from young people about what the bone marrow test entails.

You will have received information about how to prepare your child for the test in your admission letter or from the ward staff.

In children and young people, a bone marrow test is carried out while your child is under general anaesthetic. Your child should not eat or drink for the time specified. If you do not follow these instructions, the test may be delayed or even cancelled.

The person bringing your child for the procedure should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the procedure.

On the day of the test, the doctor will explain the procedure in more detail, and discuss any worries you might have. An anaesthetist will also visit you to explain about the anaesthetic. If your child has any medical problems, for instance, allergies, please tell the doctors about these.

Once your child is under anaesthetic, the doctor will insert a hollow needle into one of their bones.

The doctor will clean the area and then insert a needle into the bone on their back at the top of the pelvis. This is usually the top of the pelvis. The doctor will then draw off the aspirate (semi-liquid bone marrow). A slightly different needle is used to get the trephine sample which is a small core of solid bone marrow. Sometimes we need to do these tests on both sides of the pelvis (bilateral) to help us make the diagnosis. The team will explain to you if this is needed for your child.

Every anaesthetic carries a risk, but this is small. Your child will be given the anaesthetic by a doctor (anaesthetist) who is specially trained to deal with any complications. After an anaesthetic some children may feel sick or vomit. They may have a headache, sore throat, feel dizzy or be upset. These side effects are short lived and not severe.

Occasionally there may be some bleeding which usually responds to pressure over the site. Rarely the bone marrow site can become infected. This skin may become red or hot and uncomfortable in the few days following the procedure. If this happens your child would need a medical review and treatment with antibiotics.

Some tests results are available within 24 hours, others may take a few days to weeks. The team will make a plan with you about when you should expect the results.

Your child will be able to recover from the biopsy on the ward. It is possible that your child will feel sick and vomit when they have come round from the anaesthetic. If this happens, we will wait until they can keep a drink down before trying to eat again. Try to encourage your child to drink fluids, but do not force them to do so.

The area where the needle was inserted will be covered with a gauze dressing which can be removed 24 hours later. You child can have a bath or shower immediately if they want. If your child is in pain, please give paracetamol according to the instructions on the bottle, unless you have been advised otherwise.

Your child will be able to go home the same day as the test. It is fine for your child to attend school the day following the procedure. However, we advise that your child avoids PE or sports for a week.

You should call your GP or the hospital if:

• the biopsy site bleeds
• the biopsy site oozes a lot of fluid or becomes hot red and painful
• your child is not drinking fluids

Further information and support

Call the GOSH switchboard on 0207405 9200 and ask for the ward from which your child was discharged.