The transfusion of donated blood and blood parts from one person to another can save lives: not only is blood needed when there is a large loss of blood, but the various components that make up blood can be used for treating certain illnesses.
Why is there a need for a blood transfusion?
More than 25% of people living in the UK will need a blood product at least once in their lifetime, and every day in England about 8,000 blood transfusions are performed.
Most people have lost a small or moderate amount of blood from a cut or scrape on more than one occasion, and in these amounts it can be easily replaced with other fluids in the body and new blood cells, which form every day. However, if a large volume of blood is lost during childbirth, from a major injury or from a surgical procedure, it needs to be replaced.
Blood components are also used to replace those components that have formed abnormally due to a medical disorder such as sickle cell anaemia or thalassaemia, or that have been destroyed. A blood transfusion might also be necessary if someone does not have enough of a component, such as red blood cells in anaemia.
Donated blood is usually separated so the components can be used to treat different conditions:
- Red blood cells are used to replace blood loss, to treat some types of anaemia or cancers such as lymphoma, or to replace red blood cells destroyed by malaria, toxins such as alcohol or lead poisoning, or certain medicines
- Plasma is used to replace blood loss and for treating disorders in which a problem with clotting can cause bleeding
- Platelets are used for treating people with leukaemia, lymphoma, bone marrow problems, chronic liver disease or cirrhosis, and those with blood clotting problems, sepsis or severe infection.
Can any type of blood be used for a transfusion?
There are several blood types: blood groups A, B, O and AB. These blood groups refer to the type of antigen (A, B or O) on the red cells. The blood type that can be used for a transfusion depends on the patient's blood type:
- Patient with blood type A can receive blood type A or O
- Patient with blood type B can receive blood type B or O
- Patient with blood type AB can receive blood type A, B or O
- Patient with blood type 0 can receive blood type 0.
People who have type 0 blood are considered universal donors because anyone can safely receive blood from them. However, as a patient they can only receive blood from other people who have type O blood because they make antibodies to the A and B antigens. Likewise, people with blood type A cannot be given blood type B, and people with blood type B cannot be given blood type A.