Canterbury DHB
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They are caused by red cell alloantibodies, commonly after an anamnestic immune response, which occurs within 7 or 10 days of transfusion. It may also occur following de-novo production of alloantibodies, in which case the haemolysis begins several weeks to 3 months after transfusion.
There are two types of reactions:
These are estimated to occur between 1:1,605 and 1:1,899 red cell units transfused.
These reactions may go unrecognised in patients with non-specific complaints and also because they may occur after the patient has left hospital.
These vary considerably and are often clinically silent. Delayed haemolytic transfusion reactions may produce subtle clinical signs of haemolysis, with biochemical features consistent with haemolysis.
Occasionally, intravascular haemolysis may occur in association with complement, fixing alloantibodies against Duffy and Kidd groups.
Direct antiglobulin (Coombs) test and antibody screen will generally be positive. There may also be biochemical evidence of haemolysis (raised LDH, reticulocytosis, low haptoglobin).
Monitor progression of anaemia and transfuse with antigen negative units as required.
Renal insufficiency and DIC are rare, but fatalities have been reported between 6 and 16 days post transfusion.
These antibodies may wane over time and become undetectable. It is important that patients are informed of this reaction. They should be given a card or medic-alert bracelet, which contains information concerning the specificity of their red cell alloantibody.
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Topic Code: 5112
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