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Learning About Blood Transfusions

Blood vessel

What is a blood transfusion?

Blood transfusion is a medical treatment to replace the blood or parts of blood that your body has lost. The blood goes through a tube from a bag to an intravenous (I.V.) catheter and into your vein.

You may need a blood transfusion after losing blood from an injury, a major surgery, an illness that causes bleeding, or an illness that destroys blood cells.

Transfusions are also used to give you the parts of blood—such as platelets, plasma, or substances that cause clotting—that your body needs to fight an illness or stop bleeding.

How is a blood transfusion done?

Before you receive a blood transfusion, your blood is tested to find out what your blood type is. Blood or blood parts that are a match with your blood type are ordered by your doctor. Blood is typed as A, B, AB, or O. It is also typed as Rh-positive or Rh-negative.

Your blood is also screened to look for antibodies that might react with the blood that is given to you. The blood you are getting is checked and rechecked to make sure that it's the right type for you.

A sample of your blood is mixed with a sample of the blood you will receive to check for problems. Before actually giving you the transfusion, a doctor and nurses will look at the label on the package of blood and compare it to your hospital ID bracelet and medical records. The transfusion begins only when all agree that this is the correct blood and that you are the correct person to receive it.

To receive the transfusion, you will have an intravenous (I.V.) catheter inserted into a vein. A tube connects the catheter to the bag containing the blood, which is placed higher than your body. The blood then flows slowly into your vein. A doctor or nurse will check you several times during the transfusion to watch for a reaction or other problems.

What are the possible risks?

Blood transfusions have many benefits and are often life-saving. But they also have a few risks. Possible risks include:

  • Your body's reaction to receiving new blood. This may include:
    • Fever.
    • Breathing problems.
    • Allergic reaction, such as hives, swelling, or a new rash.
  • An infection from the blood. This risk is small because of the strict rules placed on handling and storing blood. Getting a viral infection, such as HIV or hepatitis B or C, through blood transfusions has become very rare. Health Canada enforces strict guidelines on the collection, testing, storage, and use of blood.
  • Getting the wrong blood type. Severe reactions, which can be life-threatening, are very rare.
  • An infection at the transfusion site, such as redness, swelling, pain, bleeding, or pus.

How can you care for yourself at home?

To prevent infection at the transfusion site

  • Wash the area daily with warm, soapy water, and pat it dry. Don't use hydrogen peroxide or alcohol, which can slow healing. You may cover the area with a gauze bandage if it weeps or rubs against clothing. Change the bandage every day.
  • Keep the area clean and dry.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

When should you call for help?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You have severe trouble breathing.

Call your doctor or nurse advice line now or seek immediate medical care if:

  • You have signs of an allergic reaction, such as hives, swelling, or a new rash.
  • You have a fever.
  • You feel weaker or more tired than usual.
  • You have a yellow tint (jaundice) to your skin or the whites of your eyes.
  • You have belly pain, nausea, vomiting, or diarrhea.
  • You have signs of an infection at the transfusion site, such as redness, swelling, pain, bleeding, or pus.

Watch closely for changes in your health, and be sure to contact your doctor or nurse advice line if you have any problems.

Where can you learn more?

Go to

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Care instructions adapted under license by your healthcare professional. If you have questions about a medical condition or this instruction, always ask your healthcare professional. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.