Blood transfusion

A blood transfusion involves taking blood from a person (the donor) and giving it to someone else.

When blood transfusions may be needed

Most blood transfusions are of red blood cells. This may be needed when:

  • there's blood loss due to bleeding
  • there's a failure to make blood which results in anaemia
  • inherited conditions mean the production of blood is faulty

Blood transfusions can be life saving but they aren't always necessary.

Consent before a blood transfusion

A healthcare professional will get your informed consent before a blood transfusion. Healthcare professionals include the doctor, nurse or midwife who is planning your treatment.

The healthcare professional should:

  • explain why you need a blood transfusion
  • discuss if there are any alternatives
  • explain potential risks or complications associated with the transfusion

You'll be given information on a blood transfusion in a standard format. It'll also be in a language that's easy to understand.

There may be circumstances when it's not possible to get consent before a transfusion. For example, if someone is unconscious after a major accident.

Further information on receiving a blood transfusion

What will happen if I don't have a blood transfusion?

If you have concerns about a blood transfusion, you should discuss these with your healthcare professional.

Realistic Medicine encourages shared decision making about your care. This means it's ok to ask questions about your care and treatment.

Preparing for a blood transfusion

Before a blood transfusion, a sample of your blood will be taken to check your blood group. This ensures that the blood you receive is compatible with your own.

If you need a special type of blood, you may carry a card to show this. You should show this card to the healthcare professional who's treating you.

Before a blood transfusion can take place, its important that you're identified correctly. This means you'll be asked to confirm your name and date of birth. This usually happens when a blood sample is taken and before a blood transfusion starts.

If you're not wearing an ID band, you shouldn't be given a transfusion.

What happens during a blood transfusion

A single unit of blood can take between 2 to 3 hours to be given. At most, it'll take 4 hours. This'll depend on how much blood is needed.

Blood is usually given through a tiny plastic tube called a cannula, which is inserted into a vein in your arm. The cannula is connected to a drip and the blood runs through the drip into your arm.

There may be some discomfort when the tube is put into the vein for a blood transfusion. You shouldn't feel anything during the transfusion.

You'll be monitored at regular intervals during a blood transfusion. This includes checking your:

  • pulse
  • blood pressure
  • temperature

If you start to feel unwell during or after, you should tell a member of staff immediately.

Safety of blood transfusions

Blood transfusions are common procedures that can save and improve lives. Death due to transfusion is extremely rare. Most patients who receive a blood transfusion experience no complications or problems.

Blood transfusion reactions

Some people may develop a reaction after a blood transfusion, including:

  • a temperature
  • chills
  • a rash

These reactions are usually mild. They can be treated with paracetamol or by slowing down the blood transfusion.

Blood transfusion risks

The risk of serious side effects after a blood transfusion is low.

Blood is taken from healthy volunteers. They complete a health questionnaire every time they donate. In Scotland, every donation is then screened for infections, including:

  • HIV
  • hepatitis B
  • hepatitis C
  • hepatitis E
  • syphilis

Other tests may be carried out if the donor has recently travelled to a country where there's malaria.

The chances of getting an infection from a blood transfusion is less than 1 in a million.

Other complications

There's a very small risk of other complications after a blood transfusion like:

  • a severe allergic reaction
  • difficulty breathing due to fluid overload
  • incompatibility due to red cell antibodies

The risks will be explained before you have a transfusion, unless this isn't possible. For example, if you need an emergency transfusion.

If serious side effects occur, staff are trained to recognise and treat them.

If you have any concerns, discuss them with your doctor, nurse or midwife.

Giving blood after you've had a blood transfusion

If you're already a blood donor, this'll enable patients to receive this lifesaving treatment.

If you've received a transfusion you're no longer able to donate blood. This is one of the many safety measures in place to protect people who receive a transfusion. If you're not sure if you've had a blood transfusion, check with your clinical team before you leave hospital.

Further information about blood donation in Scotland


Source: NHS Scotland

Last updated:
25 January 2023