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ABO incompatibility

Transfusion reaction - hemolytic; Acute hemolytic transfusion reaction; AHTR; Blood incompatibility - ABO

A, B, AB, and O are the 4 major blood types. The types are based on small substances (molecules) on the surface of the blood cells.

When people who have one blood type receive blood from someone with a different blood type, it may cause their immune system to react. This is called ABO incompatibility.

Due to modern testing techniques, this problem is very rare.

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Antibodies

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Causes

The different blood types are:

People who have one blood type may form proteins (antibodies) that cause their immune system to react against one or more of the other blood types.

Being exposed to another type of blood can cause a reaction. This is important when someone needs to receive a blood transfusion or have an organ transplant. The blood types must be compatible to avoid an ABO incompatibility reaction.

For example:

Type O blood does not cause an immune response when it is given to people with type A, type B, or type AB blood. This is why type O blood cells can be given to people of any blood type. People with type O blood are called universal donors. But people with type O can only receive type O blood.

Both blood and plasma transfusions must be matched to avoid an immune reaction. Before anyone receives blood, both the blood and the person receiving it are tested carefully to avoid a reaction. Usually, a reaction occurs because of a clerical error causing someone to receive incompatible blood.

Symptoms

The following are symptoms of ABO incompatible transfusion reactions:

Exams and Tests

The health care provider will perform a physical exam. Blood tests will usually show:

Urine tests show the presence of hemoglobin due to breakdown of red blood cells.

Treatment

In case of any reaction, transfusion should be stopped immediately. Treatment may also include:

Outlook (Prognosis)

ABO incompatibility can be a very serious problem that can result in death. With the right and timely treatment, a full recovery is expected.

Possible Complications

Complications that may result include:

When to Contact a Medical Professional

Contact your provider if you have recently had a blood transfusion or transplant and you have symptoms of ABO incompatibility.

Prevention

Careful testing of donor and recipient blood types before transfusion or transplant can prevent this problem.

References

Kaide CG, Thompson LR. Transfusion therapy: blood and blood products. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 28.

Manis JP. Blood components, product modifications, and blood donor screening. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 91.

Nester T. Blood component therapy and transfusion reactions. In: Kellerman RD, Rakel DP, eds. Conn's Current Therapy 2022. Philadelphia, PA: Elsevier; 2022:408-415.

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Review Date: 4/29/2022  

Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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