Medical Conditions

American Academy of Pediatrics

Safety of Blood Transfusions

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A quick lesson about blood

The blood in our bodies does many important things.

  • Blood carries oxygen and nutrients to all of our body’s tissues.

  • Blood helps remove carbon dioxide and other wastes from our body.

  • Blood helps fight against infections and heal wounds, and it provides all the substances that are necessary for it to clot.

Human blood is made up of several parts, and each part has a specific job.

  • Red blood cells carry oxygen from the lungs to all tissues of the body and carry carbon dioxide from those tissues back to the lungs. When red blood cells are low, this is called anemia.

  • White blood cells help the body prevent infections.

  • Platelets control bleeding by starting the process by which blood clots.

  • Plasma carries red and white blood cells and platelets throughout the body. Plasma is made up of water, nutrients, and proteins, including those that interact and combine to form clots.

Blood banks separate these parts from volunteer blood donations and have them available to transfuse separately when needed.

What are the different blood types?

There are many different types of blood. The 4 major blood types (A, B, AB, and O) are classified by the presence of certain sugars (“A” or “B” substance) on the surface of red blood cells.

Anyone can receive type O blood with the plasma removed. That is why people with type O blood are called “universal donors.” People who have type AB blood can receive blood that is type A, B, or O. That is why they are called “universal recipients.” When a transfusion is not an emergency, transfusion services try to provide people with blood matched to their type.

Blood Type



“A” substance is present.


“B” substance is present.


Both “A” and “B” substances are present.


Neither “A” or “B” substance is present.

The blood type as usually reported by a laboratory also contains information about the Rh factor. This has to do with another substance on the surface of red blood cells called “Rh” substance. The presence or absence of “Rh” substance classifies blood as positive or negative. For example, “O positive” blood is blood type O with Rh factor; “O negative” blood is blood type O without Rh factor.

It is important to know what type of blood a patient has because mixing different blood types can lead to serious medical problems. That is why blood is tested for its type and presence of Rh factor before a blood transfusion can take place.

Who needs blood transfusions?


Many types of patients may require blood transfusions. They include those

  • With severe anemia

  • With severe injuries such as those from a car crash

  • With severe burns

  • With cancer

  • Who have undergone an organ or stem cell transplant

  • Who have had heart surgery


  • Whose platelets do not work well

  • With life-threatening infections and few white blood cells

  • Whose bone marrow does not work well

Are blood transfusions safe?


  • Hepatitis B

  • Hepatitis C


  • Human T-lymphotropic virus (HTLV), a virus associated with a rare form of leukemia

  • Syphilis

  • West Nile virus


However, the most common reactions to blood transfusions are allergic (ie, itching, hives, or—in its more severe form—trouble breathing or wheezing).For that reason, transfusion should occur only under a doctor’s supervision and in a location where medical help is immediately available. This reaction occurs during or very soon after the transfusion. Be sure to tell your child’s doctor or nurse if your child starts to get uncomfortable, complains of itching, or develops hives or trouble breathing during or very soon after a transfusion. These events can be treated with medicines by mouth or by vein through an IV tube. If they occur often, the medicines can be given before the transfusion to prevent or decrease frequency of allergic reactions.

What you should know before giving consent


  • Your child’s condition and why a transfusion is needed


  • What will happen if you choose to refuse the transfusion


Where can the blood come from?

If your child needs a blood transfusion, you may be able to choose where the blood comes from. See “Blood Transfusion Options” chart.

How are transfusions done?


  • Before the transfusion begins, a small amount of your child’s blood will be tested to identify its type and to make sure it matches the donor. This is done by inserting a needle into a vein in your child’s arm (this should only sting for a few seconds) and withdrawing the blood into a test tube to be used by the laboratory.

  • Next, a sterile, single-use plastic tube (catheter) or needle (butterfly) will be placed into a vein in your child’s arm and taped in place.


  • A bag holding the blood or blood product will then be hung on a pole next to your child’s hospital bed.

  • Finally, a plastic tube will be attached from the bag to the tube or needle in your child’s arm. The transfusion begins when the contents of the bag start to flow.


Blood Transfusion Options





Autologous transfusion

A patient donates his or her own blood before surgery to be used if needed.

No risk of disease transmission or allergic reactions.

Not suitable for children younger than 9 or 10 years. Cannot be used for emergency surgery because the donation must be planned in advance. May not be possible for patients with certain medical conditions. Small risk of bacterial contamination.

Blood recycling

Blood lost during surgery is collected, cleaned, and returned to the patient.

No risk of disease transmission or allergic reactions.

Cannot be used for emergency surgery because the recycling process must be planned in advance. May not be possible for patients with certain medical conditions. Small risk of bacterial contamination.

Directed donation

Patients choose their own blood donors. For example, parents can donate blood to their children.

Patients feel safer by selecting their own donors.

Blood types must be the same or compatible. Still has a risk of disease transmission and allergic reactions. Must be planned in advance. Some hospitals do not allow this type of donation. Small risk of bacterial contamination. Donor transfusion directed by a family member may not be a good choice for individuals who could later need a bone marrow transplant. Additional costs are not usually covered by insurance.

Random donor blood

Volunteer blood donors.

Readily available; screened for diseases.

Blood types must be the same or compatible. Small risk of disease transmission and allergic reactions.

Most transfusions take 2 to 4 hours. However, if your child requires more than 1 unit of blood or requires another blood product, the transfusion could last longer. When the transfusion is over, the nurse will remove the tube or needle from your child’s arm and cover the vein with a bandage.


If your child needs to receive blood or blood products, talk with your child’s doctor about any concerns or fears you have about the procedure.

If necessary, seek out a specialist in transfusion medicine (usually a clinical pathologist affiliated with a hospital blood bank) or hematologist (medical blood specialist). Learn all you can about your child’s condition, and make sure you understand the benefits and risks of receiving blood or blood products.


Copyright © 2015 American Academy of Pediatrics. All rights reserved.

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  • 1/25/2020