Delayed haemolytic transfusion reactions (DHTR)

This is a delayed (>24 hours), immunological transfusion reaction.

When to suspect this adverse reaction?

Patients may present with unexplained fever and anaemia usually 2 to 14 days after transfusion of a red cell component.

The patient may also have jaundice, high bilirubin, high LDH, reticulocytosis, spherocytosis, positive antibody screen and a positive Direct Antiglobulin Test (DAT).(1,2)

It occurs in 1:2500 to 1:11 000 of transfusions.(1,3)

Usual causes?

After transfusion, transplantation or pregnancy, a patient may make an antibody to a red cell antigen that they lack. If the patient is later exposed to a red cell transfusion which expresses this antigen a DHTR may occur.

DHTRs may also occur with transfusion transmitted malaria and babesiosis.(2)

The clinical severity of a DHTR depends on the immunogenicity or dose of the antigen. Blood group antibodies associated with DHTRs include those of the Kidd, Duffy, Kell and MNS systems, in order of decreasing frequency.(1)


Request a Direct Antiglobulin Test (DAT), antibody screen, liver function tests (LDH) and markers of haemolysis (eg serum haptoglobin, bilirubin).

What to do?

Most delayed haemolytic reactions have a benign course and require no treatment, however life-threatening haemolysis with severe anaemia and renal failure may occur.(2)

If an antibody is identified, you may request antigen-negative blood if further transfusion is needed.

  1. Roback JD (ed). Non-infectious complications of blood transfusion. Chapter 27, AABB Technical Manual, 17th edition. AABB, Bethesda, 2011.
  2. Callum JL, Lin Y, Pinkerton PH, Karkouti K, Pendergrast JM, Robitaile N et al. Chapter 5, Transfusion Reactions. Bloody Easy 3: Blood Transfusions, Blood Alternatives and Transfusion Reactions: A Guide to Transfusion Medicine, 3rd edition. Canada: Ontario Regional Blood Coordinating Network, 2011. [cited 2012 Sep 13]. Available from:
  3. Popovsky M (ed). Transfusion reactions, 3rd edition. AABB Press, Bethesda, 2007.