What is a blood transfusion?

Blood transfusions are a simple way of treating anaemia, which is a low number of red blood cells. When you have a blood transfusion you are given blood from carefully screened donors.

The transfusion increases the number of red blood cells in your blood. This means that more oxygen can be carried around the body to your tissues and organs. This will increase your energy levels and reduce your breathlessness.

Before having a blood transfusion

Before you have a transfusion, your doctor will explain the aims of the treatment to you. They will also give you information to read. You will usually be asked to sign a form saying that you give your permission (consent) for the hospital staff to give the blood transfusion. Medical treatment can only be given with your consent.

You may decide not to have a transfusion. It is important to tell a doctor or your nurse if you decide not to have treatment, so that they can record your decision in your medical notes. You do not have to give a reason, but it can be helpful to tell the staff your concerns so they can give you the best advice.

Jehovah’s Witnesses may choose not to have some types of blood products. If this affects you, talk to your doctor about other treatments or ways of managing your anaemia.

Having a blood transfusion

If you need a blood transfusion, your doctor or nurse will first take a sample of your blood to find your blood group. This is then closely matched to donor blood. This is called cross-matching. The tests used to cross-match are done to:

  • make sure the blood is the best match for you
  • reduce possible side effects.

The blood for transfusion is stored in small plastic bags. Each bag is called a unit of blood. You will usually have 2 to 4 units of blood, depending on how anaemic you are.

Blood is given by a drip (infusion) into one of your veins. A nurse will put a short thin tube (cannula) into a vein in your arm or hand. This is then connected to a drip. If you have a central line or PICC line in place for other treatments, your nurse can connect this to your drip instead.

Transfusion of each unit of blood can take up to four hours. If you are having 1 to 2 units of blood, you can usually have it at an outpatient clinic. If you need several units, you may need to stay in hospital overnight.

You should notice an improvement in how you feel within 24 hours of having the transfusion. But for some people, the benefits may only be temporary and they may need more transfusions.

Possible side effects of blood transfusions

Reactions to blood

During the transfusion, your nurse will regularly check your temperature, pulse and blood pressure. This is to make sure you are not having a reaction to the blood. Common mild reactions can be:

  • headaches
  • a slight rise in temperature
  • a skin rash.

These effects can be relieved by drugs such as paracetamol or by slowing the transfusion down.

Severe side effects from blood transfusions are rare because blood is cross-matched first. The nurses will check you for any reactions. They will stop the transfusion and quickly treat any symptoms. Tell your nurse straight away if you have any chest or back pain, feel sick or are short of breath during your transfusion.

If you have any problems after you get home, contact the hospital.

Fluid overload

Sometimes, the amount of fluid given in a blood transfusion may put a strain on a person’s heart. This is more likely in people who have a heart condition. If you have heart problems, it may be more difficult to get rid of any extra fluid. Your doctor will give you medicine (a diuretic) for this, to help you pass the extra fluid out in your urine.

Tell your doctor or nurse straight away if you have puffiness or swelling in your hands or feet, or feel short of breath.

Iron overload

Red blood cells contain a small amount of iron. If you have lots of blood transfusions over many months, there is a very small risk that the iron can build up in your body (called iron overload). If you are at risk, you can have treatment to stop it happening. Your doctor or nurse will explain more about this.

Are blood transfusions safe?

Some people worry that the blood they are given may be infected by disease. People who donate blood are carefully screened for infection or viruses such as hepatitis or HIV. All donated blood is tested in the laboratory for infection. Rarely, these tests fail to find an infection, but the risk of being given infected blood is extremely small.

If you have any concerns about receiving a blood transfusion, talk to your doctor or specialist nurse.

Checking your details

When your blood is cross-matched, the nurse will record your name, date of birth, and identification number on the sample.

The nurses will check your details, including your blood group, several times before they give you a blood transfusion. This is to make sure you are getting the blood that has been matched for you. Before this, they put an identification band on your wrist with all of yours details on. They check this carefully, and also ask you to give your full name and date of birth before each bag of blood is given.

If you have any concerns about having a blood transfusion, talk to your doctor or specialist nurse.

Irradiated blood

Some people may need to have blood that has been treated with irradiation. This may be the case if you have had:

Your doctor will tell you if this applies to you.

Irradiated blood lowers the risk of the donated blood cells reacting against your own. The radiation will not damage the blood or make you radioactive. Your doctor will record in your medical notes if you should only have irradiated blood products.

They will also give you a special card to carry, in case you are treated at another hospital. Keep this card with you at all times and remind your hospital team that you need irradiated blood or platelets.

What is anaemia?

Anaemia is a low number of red blood cells. Many people with cancer will have anaemia at some point during their illness. This is called being anaemic. It can be due to the cancer or caused by cancer treatment. The treatment could be chemotherapy, radiotherapy and sometimes surgery.

Red blood cells contain a protein called haemoglobin (Hb), which carries oxygen around the body. If the number of red blood cells in your blood is low, you may feel very tired and have little energy. You may also become breathless.

If you have symptoms of anaemia or are having cancer treatment, you will have a blood test called a full blood count (FBC). This checks your haemoglobin level.

The normal haemoglobin level is:

  • 130-180 grams per litre of blood (g/L) for a man
  • 115-165 grams per litre of blood (g/L) for a woman.

If your haemoglobin level is low, your doctors may recommend that you have a blood transfusion.

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