What is Transfusion Reactions

Blood transfusion is associated with a number of potential side effects. These include:

  • Fever
  • Allergic reaction
  • Acute haemolysis (immediate breakdown of red blood cells)
  • Delayed haemolysis (delayed breakdown of red blood cells)
  • Anaphylaxis (severe allergic reaction)
  • Transmission of infection – Hepatitis B virus, Hepatitis C, and HIV are the most important
  • Electrolyte toxicity (for example low calcium, high potassium)
  • Iron overload

Statistics on Transfusion Reactions

All transfusion reactions are uncommon: most are very rare. Approximate risk rates are given below:

  • Fever: 2:100
  • Allergic reaction (mild): 2:100
  • Acute haemolytic reaction: 1:12 000
  • Delayed haemolytic reaction: 1:1000
  • Anaphylaxis: 1:150 000
  • Hepatitis B transmission: 1:66 000
  • Hepatitis C transmission: 1:100 000
  • HIV transmission: 1:700 000

Risk Factors for Transfusion Reactions

Rigorous checks and screening of blood for compatability and blood-borne infections are carried out in Australia and throughout the Western world. Failure to perform these procedures would predipose to acute haemolysis and transmission of infection. Patients with previous mild allergic reactions to blood transfusion are more likely to suffer this side effect. Deficiency of IgA antibodies in the bloodstream (rare) can predispose to anaphylaxis reactions. Transfusion of large amounts of blood predisposes to electrolyte disturbance and iron overload.

Progression of Transfusion Reactions

  • Fever: antibodies are present in the recipient which are directed against donor white blood cells
  • Mild allergic reaction: an immune response is directed against various plasma proteins present in donor blood
  • Delayed haemolytic reaction: previous transfusion primes the recipient’s immune system to reject donor cells during the next transfusion (alloimmunisation).
  • Acute haemolytic reaction: antibodies to donor red blood cells are already present in the recipient. For example, a recipient with ‘B’ blood group has antibodies to ‘A’ group blood; if group A blood is given the recipient’s immune system will destroy the cells. Recipients with blood group ‘O’ can only recieve group ‘O’ blood, as they have antibodies to both group A and group B red blood cells.
  • Anaphylaxis – patients with Ig A antibody deficiency may be sensitive to this type of antibody. Donor blood with IgA sets off a severe allergic response in the recipient.
  • Infections: Hepatitis A, B, HIV are all blood-borne viruses which can survive in stored blood and will infect the recipient if present in transfused blood
  • Electrolyte toxicity – low calcium may occur due to the presence of citrate in transfused blood. Citrate is added to prevent blood from clotting while it is stored, however it may (rarely) cause low calcium in blood recipients. Potassium levels increase the longer blood is stored, as it leaks out of blood cells. This is only a problem if very large amounts of blood are transfused.

How is Transfusion Reactions Diagnosed?

Group and crossmatch of the donor and recipient blood should be done prior to the transfusion being given. When giving blood transfusion, the patient’s vital signs (blood pressure, respiratory rate, pulse rate, temperature) are monitored. The¬†patient is observed for evidence of an adverse reaction.

An ECG may be necessary if large amounts blood has been given, or in neonatal or hypothermic patients (greater chance of hypocalcaemia).

Blood biochemistry analysis may be needed to assess possible electrolyte disturbance, especially in patients recieving large volumes of blood. A full blood count should be done

Prognosis of Transfusion Reactions

Complications of blood transfusions may be fatal; for example, acute haemolysis, anaphylaxis, or HIV transmission. For this reason, great care is taken in ensuring that blood is adequately screened, cross-matched, and correctly administered.

How is Transfusion Reactions Treated?

The primary treatment of blood transfusion reactions is prevention. This is acheived through:

  • Careful screening of donated blood for infection
  • Careful matching of donors and recipients to avoid ABO blood group incompatability and acute haemolysis reactions
  • Using the same donor if many transfusions are needed
  • Reducing white blood cells in donor blood

If low calcium or high potassium is a severe problem, calcium gluconate can be given. If a haemolytic transfusion reaction occurs:

  • Acute – check all documentation to detect errors. Stop transfusion. Urgent blood grouping.
  • Delayed – Check antibodies and monitor patient.

Transfusion Reactions References

  1. Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002 Pg 427-430.
  2. Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001