Blood transfusion

What is a blood transfusion?

A blood transfusion is a procedure in which you are given blood or blood products through a vein. The procedure has to be done in hospital or a healthcare facility. 

Where does blood for a transfusion come from? 

In New Zealand, blood comes only from unpaid and voluntary donors. 

Red blood cells are needed to carry oxygen around your body to help your body function properly. You might need a blood transfusion because you don't have enough blood or red blood cells. 

This can happen when:

• you have lost a lot of blood in an emergency situation, eg, in an injury or surgery
• you have lost too much blood for other reasons, eg, heavy bleeding during a menstrual period or stomach ulcers causing bleeding inside your body
• your body is not producing enough red blood cells to carry oxygen around your body, eg, due to iron deficiency (anaemia)
• your body is destroying too many red blood cells, eg, due to chemotherapy.

A blood transfusion is an extremely safe procedure and treatment. It can save many lives.

Before donor blood is given to you, it is always tested and screened for infections such as HIV/AIDS, hepatitis B, hepatitis C and syphillis. Both your blood and the donor blood are also tested to check for blood group types and antibodies to avoid a reaction due to them not being compatible.

The equipment used to collect blood are all sterile and only used once. 

Your doctor will weigh the benefits against the risks of you having a blood transfusion. If your doctor recommends a blood transfusion, that will mean the benefits are greater than the risks. 

Blood components that are used in a blood transfusion include:

• red blood cells – used to replenish the red blood cells lost in anaemia or severe bleeding
• platelets – tiny blood cells to stop bleeding
• fresh frozen plasma and cryoprecipitate – used to replace proteins for blood clotting.

Your doctor will advise how much blood you need. Most people get better after just one unit of blood transfusion. However, some people will need more blood.

You may need more blood if you have:

• severe bleeding that is hard to control
• severe anaemia and severe chest pain. 

Although blood transfusion in New Zealand is generally safe, the risks increase if you get more blood. Read more about the risks of a blood transfusion. 

Recent research found that extra units of blood are not helpful if you don't need them. Read more about blood transfusions for anaemia in hospital – how much do you need?(external link) Choosing Wisely, NZ

There are other alternatives to a blood transfusion. These include the following:

• No transfusion – this is when the risks from not having a transfusion are greater than the risks from having a transfusion, so it is not recommended. 
• Blood substitutes – there is no routine use of blood substitutes for red blood cells, platelets or plasma so far.  
• Providing blood for yourself – this is also called autologous blood collection. Your blood is collected for your own use in the future. Read more about donating blood for yourself(external link)(external link).
• Directed donations – blood is collected from your relatives or friends. This is not recommended by the New Zealand Blood Service. 

Talk to your doctor to find out what alternative is best for you. 

Your doctor or nurse will explain to you about the process of a blood transfusion, including the risks and side effects. You will need to sign a consent form if you agree to receive a blood transfusion. This is a good time to ask your health providers any questions relating to the process. Your blood sample will also be taken and tested for blood group types and antibodies and matched with donor blood to prevent a reaction due to lack of compatibility. 

Before any blood is given to you, a nurse will check your identification to ensure you are given the correct blood. Similar to a blood test, you will feel a prick or sharp sting when a needle is inserted into your vein, and some pressure when the blood is flowing into your vein. However, you should not feel any pain or discomfort during the process. A nurse will monitor you to make sure you feel fine throughout. 

The time a blood transfusion takes depends on the amount of blood you are receiving. It can range from 1–4 hours. 

The risks of a blood transfusion include:

• temporary reactions such as a mild fever or skin rash
• an incompatibility reaction such as kidney failure, breathing difficulties and other life-threatening complications, but this is rare
• a mild allergic reaction such as a rash or more severe allergic reaction such as fainting, breathing difficulties or cardiac arrest
• minor virus infections, but this happens only occasionally
• more serious infections such as hepatitis B and C, HIV/AIDS and HTLV-1 virus are very rare as screening of these infections are done before the procedure, but they can be serious and life-threatening in some cases
• the desired effect of a blood transfusion not being achieved.