Blood is pumped by the heart around the body in tubes called blood vessels.
Arteries carry blood from the heart to the rest of the body.
Veins carry blood from the body back to the heart.
Blood carries oxygen and nutrients around the body and takes away waste so that we stay healthy.
Blood is made up of:
Plasma
Plasma is the liquid part of blood. It is made up of water, proteins, nutrients, hormones and waste products.
Serum is plasma but with some of the proteins removed.
Blood cells
There are three types of blood cells, the living parts of blood. Bloods cells are made in the bone marrow, which is found in the long bones in the body, like the leg bones.
Red blood cells carry oxygen round the body. They do this in a substance called haemoglobin. Red blood cells are often called RBCs or erythrocytes (“erythro” means red and “cyte” means cell).
White blood cells help fight infection. They are part of the immune system, which is the body's way of defending itself against disease, bacteria and viruses. White blood cells are often called WBCs or leucocytes (“leuco” means white).
Platelets help blood to clot, or form clumps. When you cut yourself, blood clots help to heal the wound.
Why does my child need a blood test?
Your nurse or doctor will tell you why your child is having a blood test, and when you will get the results. Common reasons for testing blood in children include:
- to find out more about their general health
- to find out if they have a specific condition, including those that affect the urinary system and kidneys
- to find out if they have an infection
- to check how well their kidneys are working
- for children who have a kidney disease, to find out if their kidney function is getting worse
- to check if treatment is working, look out for any side effects from treatment and help your doctor to adjust any treatment. This can include checking the blood levels of some medicines.
- before a blood transfusion (receiving blood from someone else (a blood donor)
What are the blood tests looking for?
Blood tests can help find out:
- if your child has the right amount of important chemicals in their body – including minerals called electrolytes and the waste products urea and creatinine
- if your child has any complications from their kidney disease such as effects on their bones or heart
- if your child has an infection
- the number of different types of blood cells – a full blood count - as these can be affected by kidney disease
- your child’s blood group – this is important if they need an operation or blood transfusion