Blood Transfusion Procedures

A blood transfusion is a common procedure in which a donor’s blood is infused into the patient’s blood to help replace missing blood components. Patients can receive red blood cells, white blood cells, platelets or plasma. Before receiving a transfusion, donor blood undergoes a rigorous screening process and medical staff must perform many safety measures to ensure that the patient’s transfusion is administered safely.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Blood Typing

It is imperative that the donor blood a person receives matches the patient’s own. Laboratories determine a person’s blood type based on the presence or absence of A or B antigens. According to the National Institutes of Health, antigens are a chemical response that produces an immune response in the body 24. For example, B blood types will have only B antigens. Each blood type also has anti-antigens that will cause the body to have a severe immune reaction. Blood types A have a B anti-antigen, meaning that if they receive type B blood, they will suffer from a hemolytic reaction, which causes blood cells to burst and leak toxins into the bloodstream. Blood typing also examines the Rh factor 2. People are Rh positive or Rh negative. Giving positive blood to a person with a negative blood type will not initially cause a reaction but could result in a severe or fatal transfusion reaction in later transfusions.


Crossmatching is the second step in the blood transfusion process. After the donor’s blood and recipient’s blood are typed and Rh factor is determined, both blood samples will undergo screening for specific chemicals known as antibodies to avoid a reaction. Laboratories must repeat this process for every blood transfusion the patient receives.

According to the University of Michigan, before a blood transfusion, patients must sign a piece of paper known as an informed consent 3. An informed consent form ensures that the patient is aware of how the procedure works and the risks, the benefits and any alternatives. A physician, a nurse or a physician’s assistant must obtain the informed consent. Before the transfusion, the nurse will verify through a series of blood component and patient identifiers that the right blood is being given to the right patient.

Transfusion Process

Before the transfusion, a set of vital signs will be taken determining the patient’s temperature, heart rate, breathing rate and blood pressure. This will serve as a baseline during the transfusion. The nurse administers the transfusion via an intravenous catheter placed into the vein. Nurses will monitor the patient closely for the first 15 minutes and then take another series of vital signs looking for any symptoms of a reaction to the blood components. Reaction symptoms include:

  • rash
  • itching
  • fever
  • bloody urine
  • chills
  • back or chest pain

The nurse will collect vital signs again after 30 minutes and every hour after until the transfusion is complete.

Adverse Reactions

In the event that a patient experiences a minor allergic reaction including itching, hives or a mild fever, physicians may choose to treat with an antihistamine known as diphenhydramine rather than stop the transfusion. In the event of a severe reaction, the nurse will immediately stop the transfusion and blood from both the patient and the donor will be sent to the lab for further analysis. Physicians will often prescribe antihistamines to control itching and rash, corticosteroids to control the immune response and possibly fluids and diuretics to prevent kidney failure.