A blood transfusion is when you receive donated blood in a hospital or other medical setting. It can help you if you’ve lost blood (due to surgery or trauma, for example) or you have a condition that affects your blood cells. These side effects are usually mild and may include an allergic reaction or fever.
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Your healthcare providers will take a blood sample to find out your blood type so they know what blood type is safe for you to receive. Providers may use blood type 0 negative if you need a transfusion right away. They’ll explain potential reactions and risks.
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In most cases, you’ll need to give informed consent before receiving a blood transfusion. This means you read and sign a document that explains the procedure’s purpose, benefits, risks and alternatives. There may be situations when you can’t give informed consent, like having life-threatening injuries from an accident. In that case, healthcare providers will try to reach your next of kin or someone who has power of attorney.
In general, healthcare providers will:
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Red blood cell transfusions and whole blood transfusions take about two to four hours. Plasma transfusions and platelet transfusions are quicker and may take up to one hour.
Your healthcare provider will explain what you should do if you have a reaction to the blood transfusion. Unless you need other treatment, you’ll be able to go home after your transfusion. They may recommend that you rest for the next 48 hours. The arm that had the IV in it may be sore. Putting a cold compress on your arm and keeping it elevated might help with soreness.
A blood transfusion can save your life if you lose a lot of blood from surgery or an injury. It can also be a treatment for blood disorders and certain kinds of cancer.
Blood transfusions are generally safe. Your healthcare provider will explain possible risks, like an allergic reaction or a fever from a transfusion. They’ll also explain the risk that you’ll have a more severe reaction. It’s important to remember your provider will only recommend a blood transfusion if the benefits outweigh possible risks.
Potential risks include:
Your recovery depends on many factors, including the condition the transfusion is treating. Talk to your healthcare provider to learn more about what you can expect and any future treatments you might need.
Blood transfusion reactions can happen during the transfusion, the next day or up to several months later. Call your healthcare provider right away if you experience:
Like other medical treatments, you can say no to a blood transfusion. Your healthcare provider may ask why you don’t want this treatment. They’ll explain why they recommend it and what could happen if you don’t have it. This is your opportunity to share your concerns, ask questions and get the information you need to feel confident about your choice.
We all have blood running through our veins, and we all need it to survive. And every day, healthcare providers transfer blood that once ran through someone else’s veins into another person’s body. A blood transfusion may save your life or help treat a serious illness.
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But getting blood from someone else isn’t simple or risk-free. Your healthcare provider will explain why they recommend this treatment. They’ll also talk to you about the process, including any possible risks, and what you can expect. Don’t hesitate to share any questions or concerns with your provider. They can help you feel more comfortable with what’s happening and explain why a blood transfusion is important for your care.
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When you want expert blood disorder care, look no further than Cleveland Clinic. Our hematology experts offer personalized care and support.
Last reviewed on 08/26/2025.
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