Overview
Transfusion Reactions
Topic Overview
Summary
Transfusion reactions are adverse events occurring during or after blood transfusion. They range from mild febrile reactions to life-threatening ABO incompatibility or TRALI (transfusion-related acute lung injury). Any new symptom during transfusion should prompt stopping the transfusion and assessment. Key reactions include febrile non-haemolytic (most common), allergic/anaphylactic, acute haemolytic (most dangerous), TACO, and TRALI. Management depends on type and severity.
Key Facts
- Most common: Febrile non-haemolytic transfusion reaction (FNHTR)
- Most dangerous: Acute haemolytic reaction (ABO incompatibility)
- Pulmonary: TRALI (immune) vs TACO (fluid overload)
- Key action: STOP transfusion, check patient ID and blood label
- Report: All reactions must be reported to blood bank
Clinical Pearls
Any symptom during transfusion = stop and assess; don't assume it's benign
ABO incompatibility = usually clerical error — CHECK the labels
TRALI = acute lung injury within 6 hours; TACO = fluid overload (raised JVP, oedema)
Why This Matters Clinically
Transfusion reactions can be fatal. Rapid recognition, stopping the transfusion, and appropriate management save lives. Prevention starts with correct patient identification.
Visual Summary
Visual assets to be added:
- Transfusion reaction types comparison table
- TRALI vs TACO comparison
- Acute transfusion reaction algorithm
- Blood bag checking procedure
Epidemiology
Incidence
| Reaction | Incidence |
|---|---|
| Febrile non-haemolytic | 1-3% of transfusions |
| Allergic (mild) | 1-3% |
| Anaphylaxis | 1 in 20,000-50,000 |
| Acute haemolytic | 1 in 40,000 |
| TACO | 1 in 100 (elderly, cardiac disease) |
| TRALI | 1 in 5,000-10,000 |
Risk Factors
| Factor | Notes |
|---|---|
| Multiple previous transfusions | Alloimmunisation |
| Multiparous women | HLA antibodies |
| IgA deficiency | Anaphylaxis to IgA |
| Cardiac disease, fluid overload | TACO |
| Critical illness | TRALI |
Pathophysiology
Febrile Non-Haemolytic (FNHTR)
- Cytokines accumulated in stored blood
- Recipient antibodies to donor WBC antigens
- Temperature rise over 1°C
Allergic/Anaphylactic
- IgE-mediated reaction to plasma proteins
- Severe: IgA-deficient patients with anti-IgA antibodies
Acute Haemolytic Transfusion Reaction (AHTR)
- ABO incompatibility (usually clerical error)
- Pre-formed antibodies attack transfused RBCs
- Intravascular haemolysis → haemoglobinaemia, haemoglobinuria
- DIC, renal failure, death
TRALI (Transfusion-Related Acute Lung Injury)
- Donor antibodies (anti-HLA, anti-HNA) activate recipient neutrophils
- Neutrophil accumulation in lungs → capillary leak → pulmonary oedema
- Non-cardiogenic
TACO (Transfusion-Associated Circulatory Overload)
- Volume overload
- Cardiogenic pulmonary oedema
- Risk: Elderly, cardiac disease, rapid/large transfusion
Clinical Presentation
Features by Reaction Type
| Reaction | Features |
|---|---|
| Febrile (FNHTR) | Fever, rigors; no other features |
| Allergic (mild) | Urticaria, pruritus |
| Anaphylaxis | Hypotension, bronchospasm, angioedema |
| Acute haemolytic | Fever, rigors, chest/back pain, hypotension, dark urine |
| TRALI | Acute dyspnoea, hypoxia, bilateral infiltrates (within 6h) |
| TACO | Dyspnoea, raised JVP, oedema, hypertension |
Timing
Red Flags
| Finding | Significance |
|---|---|
| Hypotension + fever + rigors | Haemolysis or sepsis |
| Dark (red/brown) urine | Intravascular haemolysis |
| Acute respiratory distress | TRALI or TACO |
| Anaphylaxis | Severe allergic — adrenaline |
Acute reactions
During or within 24 hours
Delayed reactions
Days to weeks later (delayed haemolytic, iron overload)
Clinical Examination
Vital Signs
- Temperature (fever)
- BP (hypotension in severe reactions)
- Heart rate
- Oxygen saturation
- Respiratory rate
Cardiovascular
- JVP (raised in TACO)
- Oedema
Respiratory
- Crackles (pulmonary oedema)
- Wheeze (anaphylaxis)
Skin
- Urticaria
- Flushing
- Angioedema
Investigations
Immediate
| Test | Purpose |
|---|---|
| Check patient ID and blood bag | Confirm correct patient |
| Repeat group and crossmatch | Confirm compatibility |
| Direct antiglobulin test (DAT) | Positive in haemolysis |
| Blood cultures | Bacterial contamination |
| FBC | Hb drop |
| U&E, LFTs | Organ function |
| Bilirubin, LDH, haptoglobin | Haemolysis |
| Urinalysis | Haemoglobinuria |
TRALI vs TACO
| Feature | TRALI | TACO |
|---|---|---|
| JVP | Normal | Raised |
| BP | Low/normal | High |
| BNP | Normal | Raised |
| Response to diuretics | Poor | Good |
| CXR | Bilateral infiltrates | Pulmonary oedema |
Blood Bank
- Return blood bag and giving set
- Report to transfusion laboratory
- Complete incident form
Classification & Staging
Acute Reactions (Under 24 Hours)
| Type | Mechanism |
|---|---|
| Febrile non-haemolytic | Cytokines/antibodies to WBCs |
| Allergic | IgE to plasma proteins |
| Anaphylaxis | Severe IgE; anti-IgA |
| Acute haemolytic | ABO incompatibility |
| TRALI | Donor antibodies → lung injury |
| TACO | Volume overload |
| Bacterial contamination | Infected unit |
Delayed Reactions (Days to Weeks)
- Delayed haemolytic
- Transfusion-transmitted infection
- Iron overload
- Alloimmunisation
Management
Immediate Actions — All Reactions
| Step | Action |
|---|---|
| 1 | STOP the transfusion |
| 2 | Keep IV line open (saline) |
| 3 | Check patient ID against blood bag |
| 4 | Take observations (vital signs) |
| 5 | Notify medical team and blood bank |
| 6 | Return bag and giving set to lab |
Specific Management
Febrile (FNHTR):
- Paracetamol
- May restart transfusion if only mild fever
Allergic (Mild):
- Antihistamine (chlorphenamine 10mg IV)
- May restart cautiously
Anaphylaxis:
- IM adrenaline (0.5mg = 500mcg)
- IV fluids
- Oxygen
- Steroids
- Do NOT restart transfusion
Acute Haemolytic:
- Aggressive IV fluids (maintain urine output over 1mL/kg/hr)
- Monitor for DIC, renal failure
- ITU if shocked
- Inform blood bank urgently
TRALI:
- Stop transfusion
- Oxygen, supportive care
- May need intubation/ICU
- Do NOT give diuretics (not fluid overload)
TACO:
- Stop transfusion
- Sit patient up
- Oxygen
- IV diuretics (furosemide)
Complications
Acute Haemolytic
- DIC
- Acute kidney injury
- Death
TRALI
- ARDS
- Respiratory failure
- Death (5-10%)
TACO
- Pulmonary oedema
- Hypoxia
Prognosis & Outcomes
Prognosis
| Reaction | Outcome |
|---|---|
| FNHTR | Excellent |
| Allergic (mild) | Excellent |
| Anaphylaxis | Good if treated promptly |
| Acute haemolytic | 10-40% mortality |
| TRALI | 5-10% mortality |
| TACO | Good if treated |
Evidence & Guidelines
Key Guidelines
- BCSH Guideline on Administration of Blood Components
- SHOT (Serious Hazards of Transfusion) Annual Reports
Key Evidence
- Correct patient identification prevents most fatal reactions
- Leucodepletion has reduced FNHTR
Patient & Family Information
What is a Transfusion Reaction?
A transfusion reaction is when your body reacts to donated blood. Most reactions are mild, but some can be serious.
Symptoms to Report
- Fever or chills
- Rash or itching
- Difficulty breathing
- Feeling unwell
What Will Happen?
- The transfusion will be stopped
- You will be checked by doctors and nurses
- Treatment will be given if needed
Resources
References
Primary Guidelines
- BCSH. Guideline on the Administration of Blood Components. 2012 (updated). b-s-h.org.uk
- SHOT. Annual Report and Summary. shotuk.org
Key Reviews
- Tinegate H, et al. Guideline on the investigation and management of acute transfusion reactions. Br J Haematol. 2012;159(2):143-153. PMID: 22928769