Blood cancer and blood transfusions

Blood cancer and its treatment can affect how your body makes blood cells, or destroy blood cells you already have. This can cause you to have low levels of healthy blood cells (low blood counts).

Blood transfusions do not treat the blood cancer itself, but they do give you replacement healthy blood cells. This can help relieve symptoms and side effects caused by low blood counts, such as tiredness, breathlessness, bleeding or increased risk of infections.

Blood transfusions are a type of supportive care.

There are different types of blood transfusion, each containing different blood cells or components of blood. If your doctor recommends a transfusion, they will explain which type you need and the benefits and risks.

Red blood cell transfusions are the most common type of transfusion. Your doctor might recommend you have one if you have anaemia – a low level of red blood cells. This is measured as haemoglobin on a blood test. Haemoglobin is a protein in red blood cells that carries oxygen from your lungs to the rest of your body.

Red blood cell transfusions are one type of treatment for anaemia. They can help relieve the symptoms by increasing your level of red blood cells and haemoglobin. Symptoms of anaemia include feeling very tired, breathless and dizzy.

Platelets are a type of blood cell that help your blood to clot. They stick together to stop bleeding if you have a cut or a bruise. You may need a platelet transfusion if the level of platelets in your body becomes too low and you’re at risk of bleeding.

Plasma is the liquid part of your blood. It contains proteins that help your blood to clot. You might have plasma transfusions if you have severe problems with bleeding or blood clotting.

In rare cases, if your white blood cell level is very low and you have a severe infection, you might have a transfusion of granulocytes. Granulocytes are a type of white blood cell that help to fight infection.

You usually have blood transfusions at the hospital as an outpatient, unless you are already staying in hospital for treatment. You might need to stay overnight if your blood levels are very low and it’s not safe for you to be at home until you’ve had the transfusion.

There are a few steps to having a blood transfusion. A nurse will care for you throughout the process.

Before the blood transfusion:

• You will be asked to sign a consent form. This should explain what the transfusion is, why you need it and possible side effects.
• You will have a blood test to make sure the blood you receive is well matched to yours.
• You will be given a time for your transfusion.

During a blood transfusion:

• You sit in a chair or lie in bed.
• The nurse will check your ID and apply a wristband.
• The nurse inserts a thin plastic tube into a vein, usually in your arm. If you have a central line, you can have the transfusion through this instead.
• The nurse will check the bag of blood to make sure it’s compatible, before connecting it to the tube.
• The blood flows through the tube into your body.
• The nurse will check your blood pressure, pulse and temperature regularly throughout the transfusion.

After a blood transfusion:

• Once the transfusion is finished, the nurse removes the tube (unless you have a central line that is staying in).
• The nurse will check your blood pressure, pulse and temperature again. If everything is OK and you are feeling well, you can go home unless you are staying in hospital for treatment.

Red blood cell transfusions can take up to four hours per bag (unit). Platelet and plasma transfusions usually take between 30 to 60 minutes per bag.

Your doctor or nurse will let you know how many bags you need and how quickly you will receive them.

It can take a few hours to have a transfusion so you may want to take some snacks and something to keep you occupied.

Blood transfusions are generally very safe. There are several ways that blood transfusions are made as safe as possible.

Severe side effects from blood transfusions are rare. This is because the blood is screened first and checked to make sure it’s the right match for you.

During the transfusion, a nurse will check your temperature, pulse and blood pressure. Some people have mild reactions like a high temperature, chills or a rash. These can be reduced with drugs such as paracetamol or by slowing down the transfusion.

There’s a very small risk of having an allergic reaction to the donor blood. Tell the nurse straight away if you start feeling unwell during the transfusion. If your nurse notices any reaction, they can stop the transfusion quickly.

You should tell your hospital team if you feel unwell after you get home.

Some people need to receive blood treated with radiation (irradiated blood). This is to prevent a condition called transfusion-associated graft-versus-host disease (GvHD), where white blood cells from the donor blood attack other cells in your body.

If you need irradiated blood your hospital team should give you an alert card to carry at all times. Make sure you show your card if you have treatment somewhere else, as they may not have access to your record from your usual hospital.

People who should have irradiated blood include:

• people with Hodgkin lymphoma, including those who have had it in the past
• stem cell donors (shortly before and during stem cell harvest)
• people having a stem cell transplant or CAR T-cell therapy
• people who have had certain anti-cancer drugs, including alemtuzumab, cladribine, bendamustine, fludarabine and pentostatin.

This list does not include everyone who might need irradiated blood. Always follow your hospital team’s advice and check with them if you’re unsure.

If you’ve had a stem cell transplant or CAR T-cell therapy, the length of time you will need irradiated blood for can vary. Your healthcare team will advise you.

In an emergency, if you need a blood transfusion to save your life, non-irradiated blood can be used so the transfusion isn’t delayed.

You have the right to refuse any treatment, including blood transfusions. Talk to your doctor or nurse if you have any concerns about having a blood transfusion. They will be able to explain:

• why they recommend a blood transfusion
• what might happen if you do not have a transfusion
• if there are any alternative treatment options.

It’s important to understand the risks of refusing a blood transfusion. Sometimes, there may not be any good alternatives to a transfusion. If this is the case, not having a blood transfusion could make you very unwell or even lead to death.

If you do not want blood transfusions, for example because you are a Jehovah’s Witness, it’s important to tell your hospital team as early as possible. This will help them plan your care in a way that recognises your wishes and religious beliefs.

Your team will record your wishes in your medical notes. Let them know straightaway if you change your mind.

Last full review October 2026. Next full review due October 2029. We may make factual updates to this information in between reviews.

Thank you to clinical nurse specialist Tina Brooks and specialist registrar Dr Izzy Wood for checking the clinical accuracy of this information.