What Is the Universal Recipient Blood Type?

AB positive blood is compatible with all other types

The universal recipient blood type is AB positive (also written as AB+). This means that an AB+ person can safely receive a blood transfusion with any of the other blood types. Matching the correct blood type is key to a safe blood transfusion or organ transplant.

If a person receives the wrong blood type, the body treats it as foreign. The immune system attacks the donated blood cells rather than accepting them into the body. Such an attack can lead to serious problems including kidney failure and shock. In rare cases, receiving an incompatible blood donation can be fatal.

This article reviews how blood typing works and why donor blood types need to be a safe match for their recipients. It also discusses the type-related or allergic reactions that can occur with blood transfusions.

What Is a Universal Blood Recipient?
Verywell / Emily Roberts 

Blood Types

Antigens on blood cells are what determine how a blood recipient reacts to a transfusion. An antigen is any substance the immune system can respond to. If the immune system detects an antigen that is not found on the body's own cells, it will set off an attack to fight it. 

There are seven blood types in addition to the universal recipient type. They are O positive, O negative, A positive, A negative, B positive, B negative, and AB negative. This means that:

  • O blood types are unique in that they have no antigens. O negative blood is considered the universal blood donor type. It is compatible with all A, AB, B, and O positive blood types.
  • If you have blood type A, you have an A antigen.
  • If you have blood type B, you have a B antigen.
  • The AB blood type means that both of the antigens for A and B blood are present. It is the rarest blood type. A person with AB blood has all of the antigens that are possible.

The universal donor blood type is O negative. Anyone with this type can donate blood to a person who needs it, regardless of the recipient's blood type.

Blood types are described as positive or negative. This is based on the presence or absence of a protein called Rh factor. This factor is often expressed as a "+" (positive, or present) or "-" (negative, or absent) when identifying a person's blood type.

Rh-negative blood is given to Rh-negative patients. Rh-positive or Rh-negative blood may be given to Rh-positive patients. Since both A and B antigens are present in a person with AB positive blood and it has a positive Rh factor, the recipient won't reject the blood.

Recap

The universal recipient blood type AB positive. This means that any blood type is safe to give to a person who is AB+. The person's immune system will not reject it, or mount a response to fight it.

Blood Transfusion Reactions

A person may have a reaction if they receive the wrong type of blood. An allergic reaction to the blood transfusion is also possible, regardless of the blood type.

A hemolytic transfusion reaction can occur when there is a mismatch between A, B, and O blood types of the donor and recipient. Antibodies in the recipient's blood attach to the donor red blood cells. The cells are then destroyed in the recipient's bloodstream, liver, and spleen.

Sometimes, this can lead to jaundice, or a yellow tint to eyes and skin. It also may cause uncontrolled clotting in the bloodstream, shock, and rarely death.

These reactions are divided into two categories: acute and delayed hemolytic reactions. Acute reactions happen within 24 hours of a transfusion. Delayed reactions come later, and may happen two weeks to 30 days after a transfusion. Hospital blood banks type and crossmatch each unit of blood to be given to a recipient, so these reactions are rare.

An allergic reaction to a blood transfusion is not caused by a blood type mismatch. It is caused by the recipient's body identifying the blood as a foreign invader. The immune system then works to destroy the foreign cells.

Also known as an acute non-hemolytic transfusion reaction, the symptoms of this type of reaction include:

  • Itching
  • Fever
  • Chills
  • Skin rash

The symptoms of this type of reaction often pass in a day or two. It can be treated effectively by stopping the transfusion. The person is then given an antihistamine drug such as Benadryl (diphenhydramine).

A person who has a severe type of reaction to a blood transfusion may need to have more carefully screened blood in the future. This is done to prevent a similar reaction with later transfusions.

Recap

A blood transfusion reaction may occur if the wrong type of blood is given. This is known as a hemolytic transfusion reaction, and it may occur within 24 hours of the transfusion or up to a month later. It can lead to jaundice, blood clots, and in rare cases death.

An allergic reaction to a transfusion, called an acute non-hemolytic transfusion reaction, can also occur even if the right blood type was used. It can cause a rash, itching, and fever. The reaction is treated by stopping the transfusion and giving antihistamine medication.

Organ Donation

Receiving a blood transfusion is not the only time being a universal blood recipient matters. A person who needs an organ transplant may also benefit.

A patient who needs an organ and has AB positive blood can accept an organ from donors of all blood types, just as they can accept blood of any type. However, the process of matching an organ donor with a recipient is more complicated than only matching blood type.

The organ allocation system is set up so that it's fair to people waiting for a donor organ. This way, people with AB blood don't receive an unfair percentage of organs. Neither do the recipients with other blood types receive any fewer organs. 

Summary

It's important to match blood types both for blood donations and organ transplants. The universal blood recipient type is AB positive. This means that blood of any type is safe to give to a person who is AB+. The recipient's immune system will not reject the blood.

This rejection can happen because the wrong type of blood type was given (a hemolytic reaction) or because of an allergic reaction (a non-hemolytic reaction) that isn't related to the type of donor blood. Let your healthcare provider know if you've had a blood transfusion reaction in the past.

A Word From Verywell

Individuals with AB positive blood are able to accept blood from donors of all blood types. Most of the time, there is an adequate blood supply for anyone with a need. Blood donations from a generous community make it possible for a patient of any blood type, rare or otherwise, to benefit when a blood transfusion is needed.

Frequently Asked Questions

  • What is the universal donor blood type?

    The universal donor blood type is O negative. Anyone with this blood type can donate blood to any other person regardless of their blood type.

  • Why is O negative considered the universal donor blood type?

    A person with O negative blood is a universal donor due to the lack of certain antigens on their blood cells. Antigens determine how a recipient's immune system will react to a blood transfusion. If the immune system finds an antigen it doesn't recognize, it will defend itself against what it sees as a threat.

  • What is blood transfusion?

    Blood transfusion is a medical procedure for someone low on blood or its components. They are given blood from somebody else to make up for a low blood count. The recipient's transfusion is given through an intravenous line (IV) inserted into a vein. Components of blood include plasma (carries nutrients), platelets (helps blood clotting), and red blood cells (carries oxygen).

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9 Sources
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