Clinical management
Transfusion Reactions
Identification, classification and management of immediate and delayed transfusion reactions.
Recognise and investigate
Categories from the TRACS consensus (2021). Signs overlap and severity depends on the patient; filters support reference use, not automatic case classification.
14 results
Quick reference
| Reaction | Potential severity | Timing | Mechanism | First response |
|---|---|---|---|---|
| FNHTR · Febrile non-haemolytic reaction | Variable | Acute | Mixed / variable | Pause and compare temperature with baseline; investigate hemolysis and contamination before considering resumption. |
| TAD · Transfusion-associated dyspnoea | Serious | Acute | Mixed / variable | Stop, assess oxygenation and investigate TACO, TRALI, allergy and underlying disease before classifying as TAD. |
| TACO · Circulatory overload | Serious | Acute | Non-immune | Stop and assess congestion; provide oxygen support and consider a diuretic after veterinary assessment. |
| TRALI · Transfusion-related acute lung injury | Critical | Acute | Mixed / variable | Stop and treat respiratory failure; distinguish from TACO. Ventilatory support may be required. |
| ATR · Allergic reaction, including anaphylaxis | Variable | Acute | Immune | Pause and assess airway, breathing and perfusion. Anaphylaxis requires emergency treatment, not observation alone. |
| AHTR · Acute haemolytic reaction | Critical | Acute | Mixed / variable | Stop, check identity and compatibility; assess hemolysis in the patient and bag and stabilize circulation. |
| DHTR · Delayed haemolytic reaction | Serious | Delayed | Immune | Reassess anemia and hemolysis markers; exclude blood loss and update compatibility investigations. |
| DSTR · Delayed serological reaction | Variable | Delayed | Immune | Document the antibody or new incompatibility and guide product selection for future transfusions. |
| TTI · Transfusion-transmitted infection | Critical | Acute / Delayed | Non-immune | Stop the suspect unit; retain bag and recipient samples, notify the blood bank and investigate the pathogen. |
| CIT · Hypocalcaemia / citrate toxicity | Serious | Acute | Non-immune | Measure ionized calcium and assess cardiac rhythm; correct under monitoring through access separate from blood. |
| AMM · Transfusion-related hyperammonaemia | Serious | Acute | Non-immune | Assess neurological change and liver function; investigate ammonia and other metabolic causes before attributing it to the unit. |
| HyTR · Hypotensive reaction | Serious | Acute | Mixed / variable | Stop and confirm blood pressure; assess perfusion, hemorrhage, hemolysis, sepsis and anaphylaxis. |
| PTP · Post-transfusion purpura | Serious | Delayed | Immune | Confirm count and blood smear, assess bleeding and seek specialist investigation of thrombocytopenia. |
| TA-GVHD · Transfusion-associated graft-versus-host disease | Critical | Delayed | Immune | Seek specialist assessment of cytopenias and multisystem dysfunction; retain the history of transfused units. |
Clinical details
FNHTRVariableAcuteMixed / variableDogCatFebrile non-haemolytic reactionFebrile non-hemolytic transfusion reactionNew fever: exclude haemolysis and infection before assigning FNHTR.
- How it occurs
- Inflammatory response associated with leukocytes, antibodies or product mediators. Fever alone does not establish this diagnosis.
- Signs and assessment
- New fever: exclude haemolysis and infection before assigning FNHTR.
- Initial response
- Pause and compare temperature with baseline; investigate hemolysis and contamination before considering resumption.
- Investigate
- Compare temperature before and during transfusion; examine plasma, urine and the bag if hemolysis is suspected. Fever with instability warrants a sepsis investigation.
- Prevention and planning
- Record baseline temperature and discuss leukoreduction with the blood bank. Premedication does not replace observation.
TADSeriousAcuteMixed / variableDogCatTransfusion-associated dyspnoeaTransfusion-associated dyspneaRespiratory difficulty without another defined category after investigation.
- How it occurs
- An exclusion category for respiratory distress temporally associated with transfusion that does not meet another reaction definition.
- Signs and assessment
- Respiratory difficulty without another defined category after investigation.
- Initial response
- Stop, assess oxygenation and investigate TACO, TRALI, allergy and underlying disease before classifying as TAD.
- Investigate
- Compare respiratory rate, effort, saturation and chest imaging with baseline; look for congestion, edema and pre-existing lung disease.
- Prevention and planning
- Document respiratory status and concurrent fluids before starting; record symptom onset precisely.
TACOSeriousAcuteNon-immuneDogCatCirculatory overloadTransfusion-associated circulatory overloadRespiratory signs with volume overload; assess circulation and congestion.
- How it occurs
- Delivered volume or rate exceeds the recipient’s circulatory capacity, causing congestion and hydrostatic edema.
- Signs and assessment
- Respiratory signs with volume overload; assess circulation and congestion.
- Initial response
- Stop and assess congestion; provide oxygen support and consider a diuretic after veterinary assessment.
- Investigate
- Review total volume and fluid balance. Chest imaging and cardiac assessment help distinguish congestion from other causes of dyspnea.
- Prevention and planning
- Individualize volume and rate, particularly in cardiac or renal patients; account for other fluids.
TRALICriticalAcuteMixed / variableDogCatTransfusion-related acute lung injuryTransfusion-related acute lung injuryHypoxaemia and lung injury not explained by circulatory overload.
- How it occurs
- Transfusion-associated injury to the pulmonary barrier, with edema not primarily explained by circulatory overload.
- Signs and assessment
- Hypoxaemia and lung injury not explained by circulatory overload.
- Initial response
- Stop and treat respiratory failure; distinguish from TACO. Ventilatory support may be required.
- Investigate
- Investigate hypoxemia, pulmonary edema, timing and alternative causes of lung injury. Post-transfusion dyspnea alone does not establish TRALI.
- Prevention and planning
- Document and report the implicated unit. Veterinary evidence for specific preventive strategies is limited.
ATRVariableAcuteImmuneDogCatAllergic reaction, including anaphylaxisAllergic transfusion reaction, including anaphylaxisItching, swelling or vomiting; respiratory or circulatory compromise is an emergency.
- How it occurs
- Hypersensitivity to product constituents, ranging from skin signs to anaphylaxis with systemic compromise.
- Signs and assessment
- Itching, swelling or vomiting; respiratory or circulatory compromise is an emergency.
- Initial response
- Pause and assess airway, breathing and perfusion. Anaphylaxis requires emergency treatment, not observation alone.
- Investigate
- Look for skin and gastrointestinal signs together with respiratory and circulatory changes; exclude hemolysis and contamination in systemic cases.
- Prevention and planning
- Retain reaction, product and severity history when planning future exposure. Do not assume complete protection from premedication.
AHTRCriticalAcuteMixed / variableDogCatAcute haemolytic reactionAcute hemolytic transfusion reactionRed cell destruction: investigate incompatibility and non-immune product damage.
- How it occurs
- Early red-cell destruction caused by immune incompatibility or physical, thermal or osmotic damage to the product.
- Signs and assessment
- Red cell destruction: investigate incompatibility and non-immune product damage.
- Initial response
- Stop, check identity and compatibility; assess hemolysis in the patient and bag and stabilize circulation.
- Investigate
- Check typing and crossmatch, hematocrit, bilirubin and evidence of hemoglobinemia or hemoglobinuria; review unit handling and storage.
- Prevention and planning
- Verify patient and unit at administration; select compatible blood and use appropriate equipment and solutions.
DHTRSeriousDelayedImmuneDogCatDelayed haemolytic reactionDelayed hemolytic transfusion reactionUnexpected haematocrit decline after the initial response.
- How it occurs
- Antibodies against transfused red cells shorten their survival after the initial response.
- Signs and assessment
- Unexpected haematocrit decline after the initial response.
- Initial response
- Reassess anemia and hemolysis markers; exclude blood loss and update compatibility investigations.
- Investigate
- Compare serial hematocrit with the initial response and investigate hemolysis, loss and new antibodies. A fall alone does not distinguish these causes.
- Prevention and planning
- Retain results and dates of previous transfusions; repeat compatibility assessment when indicated.
DSTRVariableDelayedImmuneDogCatDelayed serological reactionDelayed serologic transfusion reactionNewly detected antibodies without demonstrated haemolysis.
- How it occurs
- Sensitization detected by immune testing without clinical or laboratory evidence of red-cell destruction.
- Signs and assessment
- Newly detected antibodies without demonstrated haemolysis.
- Initial response
- Document the antibody or new incompatibility and guide product selection for future transfusions.
- Investigate
- Compare pre- and post-transfusion tests and check for absence of hemolysis. A new incompatible result must accompany the patient record.
- Prevention and planning
- Review compatibility before another transfusion; do not automatically reuse the previous donor choice.
TTICriticalAcuteDelayedNon-immuneDogCatTransfusion-transmitted infectionTransfusion-transmitted infectionMay present early or late; preserve the unit and samples for directed investigation.
- How it occurs
- Transmission of a donor pathogen or contamination during collection, processing or storage.
- Signs and assessment
- May present early or late; preserve the unit and samples for directed investigation.
- Initial response
- Stop the suspect unit; retain bag and recipient samples, notify the blood bank and investigate the pathogen.
- Investigate
- For suspected bacterial contamination, culture patient and product samples. For other pathogens, choose tests by species, exposure and detection window.
- Prevention and planning
- Combine donor screening, aseptic collection, storage control and traceability; negative tests do not eliminate every infection window.
CITSeriousAcuteNon-immuneDogCatHypocalcaemia / citrate toxicityCitrate toxicity / hypocalcemiaAssess ionised calcium, particularly with massive or rapid transfusion.
- How it occurs
- Citrate anticoagulant binds calcium; rapid or massive administration may lower ionized calcium.
- Signs and assessment
- Assess ionised calcium, particularly with massive or rapid transfusion.
- Initial response
- Measure ionized calcium and assess cardiac rhythm; correct under monitoring through access separate from blood.
- Investigate
- Assess ionized calcium alongside neuromuscular signs, pressure and ECG; total calcium alone does not replace this assessment.
- Prevention and planning
- Plan metabolic monitoring for massive or rapid transfusion; do not mix calcium-containing solutions in the blood line.
AMMSeriousAcuteNon-immuneDogCatTransfusion-related hyperammonaemiaTransfusion-associated hyperammonemiaNeurological changes; assess ammonia and alternative diagnoses.
- How it occurs
- Ammonia may accumulate during storage; the recipient’s metabolic capacity influences risk.
- Signs and assessment
- Neurological changes; assess ammonia and alternative diagnoses.
- Initial response
- Assess neurological change and liver function; investigate ammonia and other metabolic causes before attributing it to the unit.
- Investigate
- Investigate liver function, ammonia and other causes of altered mentation; interpret the relationship with the product and storage duration.
- Prevention and planning
- Discuss product selection and storage in patients with impaired hepatic metabolism; specific veterinary evidence is limited.
HyTRSeriousAcuteMixed / variableDogCatHypotensive reactionHypotensive transfusion reactionBlood pressure drop: exclude bleeding, anaphylaxis and other causes.
- How it occurs
- Transfusion-associated hypotension after other causes are excluded; vasoactive mechanisms may contribute.
- Signs and assessment
- Blood pressure drop: exclude bleeding, anaphylaxis and other causes.
- Initial response
- Stop and confirm blood pressure; assess perfusion, hemorrhage, hemolysis, sepsis and anaphylaxis.
- Investigate
- Confirm measurement and compare with baseline pressure; correlate perfusion, rhythm, bleeding and signs of other reactions.
- Prevention and planning
- Record blood pressure and medications before transfusion, with reassessment during administration.
PTPSeriousDelayedImmuneDogCatPost-transfusion purpuraPost-transfusion purpuraThrombocytopenia after transfusion; limited veterinary evidence.
- How it occurs
- Immune-mediated thrombocytopenia after transfusion. Veterinary reports are sparse; not every platelet decline represents PTP.
- Signs and assessment
- Thrombocytopenia after transfusion; limited veterinary evidence.
- Initial response
- Confirm count and blood smear, assess bleeding and seek specialist investigation of thrombocytopenia.
- Investigate
- Confirm true thrombocytopenia, excluding clumping; investigate consumption, infection and other immune-mediated causes.
- Prevention and planning
- Retain history and specialist assessment for future transfusions; no universal veterinary preventive protocol exists.
TA-GVHDCriticalDelayedImmuneDogCatTransfusion-associated graft-versus-host diseaseTransfusion-associated graft-versus-host diseaseRare multisystem syndrome requiring specialist investigation.
- How it occurs
- Viable donor lymphocytes may react against recipient tissues. Veterinary clinical evidence is very limited.
- Signs and assessment
- Rare multisystem syndrome requiring specialist investigation.
- Initial response
- Seek specialist assessment of cytopenias and multisystem dysfunction; retain the history of transfused units.
- Investigate
- Assess blood count and organ involvement with specialist support. Timing alone does not prove the diagnosis.
- Prevention and planning
- Discuss processing requirements with the blood bank for at-risk patients; do not automatically extrapolate human protocols.
Educational use: product selection, volume and rate require individual veterinary assessment. Follow your service protocol and supplier instructions.