Synopsis
Recognise post-transfusion haemolysis and other delayed complications, investigate new antibodies, prevent re-exposure and distinguish hyperhaemolysis, purpura and graft-versus-host disease.
- Delayed haemolytic transfusion reaction occurs more than 24 hours after transfusion, usually within days to several weeks, with haemolysis and a new or re-emergent red-cell antibody.
- Key clues are failure of the expected haemoglobin increment, a later haemoglobin fall, jaundice, dark urine, fever, pain, bilirubin or LDH rise, low haptoglobin and a new positive DAT.
- Confirmatory assessment combines repeat antibody screen and identification, DAT and eluate where appropriate, repeat crossmatch and antigen typing of patient and implicated units.
- A delayed serological transfusion reaction means a new antibody or serological incompatibility without clinical or biochemical haemolysis.
- Historical clinically significant antibodies remain binding even when the current screen is negative; future red cells must lack the corresponding antigen.
- Hyperhaemolysis destroys transfused and autologous cells, causing haemoglobin below baseline and often reticulocytopenia; avoid further transfusion unless life saving.
- First-line hyperhaemolysis management is urgent sickle or haematology specialist-led immunomodulation and supportive care, with further red cells reserved for critical anaemia.
- Post-transfusion purpura presents with severe thrombocytopenia and bleeding about 5–12 days after transfusion; high-dose intravenous immunoglobulin is first-line specialist treatment.
- TA-GVHD presents about 1–2 weeks after transfusion with fever, rash, diarrhoea, liver dysfunction and pancytopenia and has very high mortality.
- Irradiation prevents TA-GVHD by disabling donor lymphocyte proliferation; leucodepletion and CMV-negative selection do not replace irradiation.
- Reduce alloimmunisation by avoiding unnecessary transfusion and using disease-specific extended antigen matching for chronically transfused patients.
- Give the patient antibody and special-component information, update permanent laboratory records and communicate requirements across hospitals, pregnancies and emergency care.
Key red flags
A haemoglobin fall below the pretransfusion value with pain, haemoglobinuria or reticulocytopenia suggests hyperhaemolysis, particularly in sickle-cell disease.
Fever, maculopapular rash, diarrhoea, hepatitis and pancytopenia 1–2 weeks after cellular transfusion is TA-GVHD until urgently excluded.
Profound thrombocytopenia with bleeding 5–12 days after transfusion suggests post-transfusion purpura and requires same-day haematology and transfusion consultation.
Jaundice, dark urine, back pain or an unexplained loss of haemoglobin within days to weeks after transfusion requires a delayed-haemolysis screen.
A new clinically significant antibody during pregnancy can threaten the fetus and must enter the specialist obstetric antibody pathway as well as the transfusion record.
Investigation priorities
Measure red-cell or platelet loss and marrow response.
Confirm accelerated red-cell destruction and organ effect.
Management branches
Haemoglobin falls or jaundice develops more than 24 hours after transfusion.
- Send FBC, reticulocytes, bilirubin, LDH, haptoglobin, renal profile, urine and a new compatibility sample and call the transfusion laboratory.
- Repeat antibody identification, DAT and retrospective compatibility work, retrieving external and historical antibody records.
- Provide supportive care and only antigen-negative crossmatch-compatible red cells if still necessary; document the antibody permanently.