Transfusion reactions are medical complications that arise after a blood transfusion. They may occur during the transfusion (known as acute) or weeks after it (delayed). They're further classified into immunologic and non-immunologic reactions. Transfusion reactions may be minor but can sometimes be fatal.
A blood transfusion involves getting blood or blood products from another individual (a donor) through your blood veins (intravenously). This process is done to recover lost blood or blood components in your body.
A blood transfusion may be necessary if you have an underlying medical condition that causes a decrease in blood volume. Some of these conditions include:
Types of Blood Transfusions
There are three types of blood transfusions. They include:
- Plasma transfusion. Plasma is the liquid component of blood that carries proteins and other substances that are vital to your health. Plasma transfusion helps people with severe burns, liver failure, and serious infections.
- Red blood cell transfusion. A low red blood cell count could lead to conditions such as anemia and iron deficiency. A red blood cell transfusion is necessary to increase iron, hemoglobin, and oxygen concentration in the blood.
- Platelet cell transfusion. Platelets are crucial in stopping the bleeding process to prevent excessive blood loss. Medications used in the treatment of cancers like leukemia are known to cause low platelet count. People with such conditions regularly need blood transfusions to increase their platelet count.
Types of Transfusion Reactions
When getting a blood transfusion, there are many different types of transfusion reactions that may occur. These include:
- Acute hemolytic reactions. This can happen if there's red blood cell damage before the transfusion due to heat or an imbalance in the cells.
- Simple allergic reactions. This may happen if your blood is hypersensitive to protein in your donor's blood.
- Anaphylactic reactions. This is similar to a simple allergic reaction but is more severe.
- Transfusion-related acute lung injury (TRALI). Damage to the lungs occurs when your body reacts to your donor's antibodies. Your immune system responds to the reaction by releasing chemical mediators that cause edema (swelling) in the lungs.
- Delayed hemolytic reactions. This may happen when an antigen (toxin or foreign substance) gets reintroduced into your blood.
- Transfusion-associated circulatory overload (TACO). This may happen when you get too much blood in the body.
- Febrile non-hemolytic reactions. This may happen when your donor's white blood cells produce cytokines (substances that work with the immune system).
- Septic (bacteria contamination) reactions. This may happen if the blood is contaminated with bacteria or bacteria waste products.
Transfusion Reaction Symptoms
Depending on the type of transfusion reaction you get, symptoms may start to show during the transfusion or even weeks later. Common symptoms of blood transfusion reactions include:
Causes of Transfusion Reactions
Transfusion reactions may be caused by the incompatibility between your blood and your donor's blood. These types of reactions are known as immune-mediated transfusion reactions and involve antibodies that react to foreign antigens in the donor's blood.
Non-immunologic reactions can be caused by certain components contained in the donor's blood. While all donated blood is tested for potential bacteria, parasites, and viruses, some of these agents can potentially get through. Though the risk is very low, the following conditions may get transmitted through a blood transfusion:
Prevention of a Transfusion Reaction
Before a blood transfusion, healthcare providers must ensure that the recipient is receiving the correct blood sample.
Human errors, such as transfusing untested blood, are rare but can still happen. It's crucial that blood gets tested beforehand to avoid the spread of infections like HIV and Hepatitis B or C.
For blood to be passed as safe for transfusion, it has to be:
- From a donor that is free of disease
- Free of infection
- Well stored, transported, and tested for infections
- Transfused only when needed
As soon as a blood transfusion reaction occurs, doctors will need to retest the blood. This can help them understand the cause of the reaction. Your doctor may also request to retest the recipient's blood.
Most transfusion reactions are not harmful. However, some, such as anaphylactic reactions, can be fatal. Transfusion should be stopped immediately when a reaction starts and the recipient should be monitored in case of more reactions.