Full blood count to test for childhood cancer

Full blood count to test for childhood cancer

A full blood count (used in childhood cancer tests) is an examination of the blood which allows doctors to follow the course of a disease and select the right doses of the right chemotherapy medication for treatment.

What is a full blood count?

Please note: This fact sheet refers only to children having tests related to cancer. There are many other reasons why your child may be having a full blood count.

A full blood count is an examination of the blood which allows doctors to follow the course of a disease and select the right doses of the right chemotherapy medication for treatment.

A full blood count can include:

  • white blood count (WBC): this has a number of components, including neutrophils which fight bacterial infection and lymphocytes which fight viral and fungal infection and produce antibodies in the blood. A low neutrophil count is called neutropenia
  • haemoglobin (Hb) levels: haemoglobin is the pigment on red blood cells which carries oxygen around the body. A low haemoglobin count is called anaemia
  • platelet count: platelets help with clotting and a low platelet count is called thrombocytopenia

Blood for testing can be taken by a nurse and sent to the laboratory for examination. A nurse can take the blood from a small prick on your child's finger or from a central venous catheter (CVC).

If there is no CVC in place, a nurse can take some blood from a vein with a needle and syringe. A local analgesic (pain relieving cream or gel) is put on the skin before the injection. This numbs the skin so the needle prick is not felt. 

See: Pain treatment in childhood cancer and scroll down to 'topical analgesia'

Should I keep the results of my child's blood tests?

  • yes, it's a good idea to keep these together in a folder
  • after your child's doctor or nurse has explained the tests your child will need, be sure to ask for further information if you want to understand more

All the information in the Childhood cancer section of this website has been written by health professionals who work in the field of paediatric oncology. They have been reviewed by the members of the National Child Cancer Network (NZ). Medical information is authorised by the National Child Cancer Network Clinical Leader.

This page last reviewed 08 March 2013.
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