If the blood type is not a match, you can experience a transfusion reaction. You can also have a transfusion reaction if you receive blood containing infectious microbes, if you experience an allergic reaction, or if you receive too much blood.

Blood transfusions can be lifesaving in cases of blood loss. However, screening donated blood is important to ensure it goes to the right person.

This article will discuss the various transfusion reaction types, symptoms, and treatments.

If you’ve experienced severe blood loss or low blood levels, a blood transfusion can help restore the blood you’ve lost.

Also known as a hemolytic transfusion reaction, this routine procedure adds donated blood to your own as long as it’s accurately matched to your blood type.

Your doctor may recommend a blood transfusion if you’ve lost or are not producing enough blood. This can be due to the following:

Blood transfusions are most commonly done for blood components, such as red blood cells, platelets, or plasma. Before a blood transfusion, a healthcare professional will draw your blood.

This sample will be sent to a laboratory for typing and crossmatching. Typing is when the lab determines blood type. Crossmatching is testing to determine if your blood is compatible with a donor’s blood of the same type.

The blood types are:

  • A positive
  • A negative
  • O positive
  • O negative
  • B positive
  • B negative
  • AB positive
  • AB negative

Knowing your blood type is important because red blood cells contain antigens, or protein markers, corresponding to these blood types.

If a laboratory gives you the wrong type of blood, your immune system will detect any foreign proteins on the red blood cells of the wrong blood type and attempt to destroy them.

Blood banks have thorough testing processes to make sure blood is safe and correctly typed for use. A doctor or nurse will explain any risks of blood transfusions and closely monitor you while receiving the blood.

Blood transfusion reactions may occur while you’re receiving blood or immediately after. They may also occur hours, days, or weeks later. This is called a delayed transfusion reaction. Transfusion reactions may range in severity from minor to life threatening.

A doctor or nurse will stay with you while you receive the transfusion. They will check your vital signs and watch for symptoms that you may be having a reaction to.

Transfusion reaction symptoms may include:

Pay close attention to your body after a blood transfusion, and contact a doctor if you feel something isn’t right.

The following are the different types of transfusion reactions and what can cause them.

Febrile non-hemolytic reaction

This is one of the most common types of transfusion reactions. It occurs during or up to 4 hours after a transfusion is completed.


  • fever
  • chills


As always, the first step in managing a transfusion reaction is to stop the transfusion. The symptoms are generally mild and respond well to treatment with antipyretics.

Acute hemolytic reaction

This occurs when antibodies in the recipient’s blood attack the donor’s blood if the two are not compatible. The prevalence of an acute hemolytic reaction from a blood transfusion is approximately 1 in 70,000 transfusions.


  • fever
  • flank pain
  • red or brown urine
  • low blood pressure


The first step is to stop the transfusion. From there, treatment is mainly supportive. If the reaction is severe, in the case of low blood pressure, for example, aggressive resuscitation should be initiated.

Allergic reaction

You can have an allergic reaction to a blood transfusion as well. This occurs when the recipient’s immune system reacts to allergens or antigens in the donor’s blood. This type of transfusion reaction could also progress into a more severe allergic reaction known as anaphylaxis.


  • hives
  • itching
  • rash


Again, the first step is to stop the transfusion. This reaction type is often treated with antihistamines. If you are experiencing more severe symptoms like trouble breathing or swelling in your throat, your doctor may treat you with IV epinephrine, IV steroids, and bronchodilators.

Transfusion-related acute lung injury (TRALI)

This reaction may occur when donor plasma contains antibodies that cause damage to the immune cells in the lungs. This lung damage results in fluid buildup in the lungs and can severely limit the ability of the lungs to supply oxygen to the body. This reaction usually occurs within six hours of receiving blood.


  • fever
  • shortness of breath
  • low blood pressure


Immediate treatment is to stop the infusion. Supportive management is aimed at improving oxygenation.


Sometimes, bacteria may be present in the donated blood. Giving this blood to a recipient can lead to infection, shock, and death. Bacterial contamination is the second most common cause of blood transfusion-related deaths in the US. If not caught in time, it may lead to sepsis.


  • fever
  • changes in blood pressure
  • stiffness


Your doctor will treat you with IV fluids and a course of antibiotics for this transfusion reaction.

Transfusion-associated circulatory overload (TACO)

A transfusion reaction can also occur if you receive too much blood. Having too much blood can overload your heart, forcing it to work harder to pump blood through your body and resulting in fluid buildup in the lungs. TACO and TRALI are the leading causes of transfusion-related deaths.


  • rapid heart rate
  • rapid breathing
  • shortness of breath
  • high blood pressure
  • bulging neck veins
  • low blood oxygen


The first line of treatment is to stop the transfusion. Sitting upright may improve your symptoms, or your doctor may need to administer IV diuretics in more severe cases.

Blood banks make every effort to screen and test blood. A sample of recipient blood is often mixed with potential donor blood to ensure compatibility.

Before the blood is given to you, the blood label and your identity will be thoroughly checked. This ensures the doctor or nurse gives the proper blood products to the right recipient.

The following are answers to additional questions about blood transfusions.

What is the most common blood transfusion reaction?

The most common blood transfusion reactions are mild allergic and febrile reactions. Reactions like anaphylaxis or sepsis after a transfusion are rarer.

What should I watch for after a blood transfusion?

You should be mindful of signs and symptoms such as fever, chills, rash, hives, respiratory distress, low blood pressure, and red urine.

How long after a blood transfusion can you have a reaction?

A reaction can happen within 24 hours of a transfusion. They can also occur up to a month after a blood transfusion.

Transfusion reactions are not always serious. However, some can be life threatening.

If you or your healthcare professional observes blood transfusion reaction symptoms, the transfusion should be immediately stopped. A laboratory representative should come and draw blood from you and take the donated blood for testing to ensure they were matched appropriately.

Your doctor may prescribe intravenous fluids or medications to reduce the likelihood of kidney failure and shock.