A blood transfusion is the process of transferring blood or one of its components from one person to another. Blood is made of fluid called plasma and three types of blood cells: red cells, white cells, and platelets. Each part of blood has a special function and can individually transfused.
Plasma
Plasma is the fluid in blood that carries the blood cells throughout the body. It contains proteins that help the blood clot, as well as vitamins and minerals. A plasma transfusion may be needed when a child lacks the parts of the blood that help it clot.
Red blood cells
Red blood cells are the part of the blood that carries oxygen from the lungs to all other parts of the body. A certain number of these cells are needed for the body to function. Red blood cell transfusions are the most common. A child may need a red blood cell transfusion if bleeding from a trauma, surgery, or a disease that causes a low red blood cell count.
White blood cells
White blood cells are the part of the blood that fights infections by destroying bacteria, viruses, and other germs. White blood cell transfusions are very rare. They are usually reserved for children who have a low white blood cell count and severe infection that cannot be treated with antibiotics.
Platelets
Platelets are the part of the blood that helps control bleeding by forming blood clots. A platelet transfusion may be needed before an invasive procedure, such as a major surgery, that can cause a child with a low platelet count to bleed.