Introduction
Blood transfusion is a high-risk clinical procedure tested in OSCE stations for both safe administration and patient communication. You must demonstrate the pre-transfusion bedside check, correct prescription, recognition and management of transfusion reactions, and the ability to consent a patient for blood products.
💎 Clinical Pearl
Wrong blood in tube (WBIT) and wrong blood to patient are the two most dangerous transfusion errors. Every step of the pre-transfusion check exists to prevent these. Perform the check at the bedside with the patient, never at the nurses' station.
Pre-Transfusion Bedside Check — 6 Checks
🧠 Mnemonic
6 Checks before you connect:
- 1Patient identity: ask patient to state full name and date of birth; check against wristband
- 2Wristband: patient ID matches the blood compatibility label
- 3Compatibility label: on the bag — matches patient name, date of birth, and hospital number
- 4Blood group: label on bag matches patient blood group
- 5Unit number: unique unit identifier on the bag matches the compatibility form
- 6Expiry date and time: ensure blood has not expired; inspect bag for abnormal colour, clots, or discolouration
Always perform with a second checker (nurse). Document the check.
Prescribing a Blood Transfusion
On the drug chart or electronic system:
| Field | What to write |
|---|---|
| Drug | Packed Red Blood Cells (pRBC) |
| Dose | 1 unit (approximately 300 mL) |
| Route | IV (via blood administration set) |
| Rate | 1 unit over 90-120 minutes (faster if haemodynamically compromised) |
| Diuretic | Consider furosemide 20-40 mg IV with each unit in patients at risk of fluid overload (elderly, cardiac failure, CKD) |
| Monitoring | Obs (pulse, BP, temperature, respiratory rate, SpO2) before, 15 minutes after starting, and at completion |
⚠️ Red Flag
Only use a blood administration set (with 200-micron filter). Do NOT give blood through the same line as calcium-containing fluids (Hartmann's) — calcium causes clotting. Give blood with or after normal saline only.
Types of Blood Products
| Product | When used |
|---|---|
| Packed red blood cells (pRBC) | Anaemia; haemorrhage |
| Platelets | Thrombocytopaenia with bleeding; pre-procedure |
| Fresh frozen plasma (FFP) | Coagulopathy; warfarin reversal (with vitamin K) |
| Cryoprecipitate | Fibrinogen deficiency; DIC |
| Prothrombin complex concentrate (PCC) | Urgent warfarin reversal, major haemorrhage |
Transfusion Triggers
| Haemoglobin threshold | Patient group |
|---|---|
| Below 70 g/L | Most patients (transfuse to 70-90 g/L) |
| Below 80 g/L | ACS or symptomatic cardiac disease |
| Below 100 g/L | Active haemorrhage or where symptoms demand (discuss with senior) |
Transfusion Reactions
Acute Haemolytic Transfusion Reaction (AHTR)
Most dangerous — usually ABO incompatibility. Onset: within minutes.
⚠️ Red Flag
Signs: fever, rigors, back and flank pain, haemoglobinuria (red-brown urine), hypotension, tachycardia, DIC.
Management:
- 1STOP the transfusion immediately
- 2Keep IV access open with normal saline
- 3Call for senior help; inform blood bank immediately
- 4Check the unit and patient ID — confirm mismatch
- 5Send: FBC, coagulation, U+E, LFTs, direct antiglobulin test (DAT), blood cultures, urine
- 6Monitor urine output (acute renal failure risk)
Other Acute Reactions
| Reaction | Timing | Features | Management |
|---|---|---|---|
| Febrile non-haemolytic (FNHTR) | During transfusion | Fever, chills, no haemolysis | Slow or stop; paracetamol; resume if clinically safe |
| Allergic (mild) | During | Urticaria, pruritus | Stop transfusion; chlorphenamine IV; resume if resolved |
| Anaphylaxis | Minutes | Bronchospasm, hypotension, angioedema | Stop; adrenaline 0.5 mg IM; call 2222 |
| Transfusion-associated circulatory overload (TACO) | During/after | Hypertension, pulmonary oedema, dyspnoea | Stop; furosemide; oxygen; sit upright |
| TRALI | Within 6 hours | Non-cardiogenic pulmonary oedema, hypoxia, bilateral infiltrates | Stop; supportive ITU; inform blood bank |
Consenting a Patient for Blood Transfusion
Key points to cover:
- 1Why they need it (indication) — "Your blood count is low and we need to raise it to keep you safe"
- 2What the procedure involves — "We will give blood through a drip in your arm; it takes about 90 minutes per bag"
- 3Benefits — improved symptoms of anaemia, lower risk of complications
- 4Risks: fever (1 in 100), allergic reaction (1 in 100), severe reaction (very rare), infection (HIV less than 1 in 5 million, hepatitis C less than 1 in 30 million in the UK)
- 5Alternatives: iron infusion (if iron-deficiency), cell salvage (surgery), accepting anaemia if low risk
- 6Jehovah's Witness considerations: if the patient refuses blood products, respect this and document. Discuss all alternatives. Consider seeking legal advice if life-threatening in a patient who lacks capacity.
"What are the 6 pre-transfusion checks?"
1. Confirm patient identity by asking them to state their name and date of birth. 2. Check the patient's wristband matches. 3. Check the compatibility label on the blood bag matches the patient's name, date of birth, and hospital number. 4. Confirm the blood group on the bag matches the patient's blood group. 5. Verify the unique unit number on the bag matches the compatibility form. 6. Check the expiry date and inspect the bag for abnormal appearance. This must be done at the bedside with a second checker.
"What is the immediate management of an acute haemolytic transfusion reaction?"
Stop the transfusion immediately and keep the IV line open with normal saline. Call for senior help and inform the blood bank immediately. Verify patient identity against the unit and compatibility form to confirm the mismatch. Take blood samples for FBC, coagulation, U+E, LFTs, direct antiglobulin test, and blood cultures. Monitor urine output closely as acute renal failure is a major complication.
"What is the difference between TACO and TRALI?"
TACO (transfusion-associated circulatory overload) is caused by volume overload and presents during or shortly after transfusion with hypertension, pulmonary oedema, and dyspnoea. It is more common in elderly patients, those with cardiac or renal impairment, and when transfusion is given too quickly. TRALI (transfusion-related acute lung injury) presents within 6 hours with non-cardiogenic pulmonary oedema and hypoxia, is caused by anti-HLA or anti-neutrophil antibodies in donor plasma, and is typically associated with hypotension rather than hypertension.
"How do you approach a Jehovah's Witness patient who refuses blood products?"
Respect the patient's autonomy and their right to refuse blood products if they have capacity. Explore which blood products are refused — some Jehovah's Witnesses accept certain fractions or procedures like cell salvage. Document the refusal and ensure a formal advance decision is in place if appropriate. Discuss all alternatives: iron supplementation, erythropoietin, cell salvage, avoiding unnecessary blood loss. If the patient lacks capacity (e.g. unconscious), act in their best interests but take into account any known advance decisions or views.
Related guides: Prescribing Safety OSCE | IV Fluids Prescribing OSCE | A&E Assessment OSCE