Transfusion medicine handbook

7. Adverse Effects of Transfusion

7.7 Acute Haemolytic Transfusion Reaction

Incompatible red cells react with the patient's anti-A or anti-B antibodies and cause an acute haemolytic transfusion reaction (AHTR).  This can activate complement and cause disseminated intravascular coagulation (DIC) and acute renal failure. The reaction is usually most severe if group A red cells are transfused to a group O patient. Transfusion of ABO-incompatible blood almost always arises from pretransfusion sample labelling errors or from failure to perform required checks prior to giving the transfusion. If red cells are administered to the wrong patient (i.e., any patient other than the one for whom the red cells were supplied) the chances of ABO-incompatibility are about 1 in 3. Rarely, AHTR is due to a non-A, non-B, complement-fixing antibody. Such reactions reported most commonly involve the Kell, Duffy and Kidd antigen group systems.

Acute haemolysis may also occur following transfusion of plasma-rich blood components such as platelets or FFP from donors with high titres of anti-A or anti-B that react with patient red cells.

In a conscious patient even a few millilitres of incompatible blood may cause symptoms within a few minutes of starting the transfusion. The patient may become restless or distressed and experience pain at the infusion site, fever, flushing, breathlessness, or abdominal, flank or substernal chest pain. The severity varies widely as it is dependent on the titre of blood group antibody in the recipient, the quantity of blood transfused and other factors such as age. In an unconscious or anaesthetised patient, hypotension and uncontrollable bleeding due to DIC may be the only signs of an incompatible transfusion. Oliguria is common and is often followed by acute renal failure.

If AHTR is suspected, the transfusion must be stopped, the line maintained with intravenous saline and urgent steps taken to confirm or exclude this possibility.

Signs and symptoms of AHTR may be similar to a severe allergic reaction or bacterial contamination. In addition, autoimmune haemolytic anaemia due to erythrocyte autoantibodies in the recipient and non-immune (mechanical) causes must be part of the differential diagnosis.