Haematology, coagulation and transfusion

Red cell, platelet and plasma transfusion; reactions

Reviewed Nov 2026·7 references
New· views rounded down, updated weekly

Restrictive thresholds (AABB 2023), platelet and plasma indications, and recognising transfusion reactions (TACO, TRALI, haemolysis).

Definition
Restrictive transfusion is safe for most critically ill adults: transfuse red cells at Hb < 7 g/dL; higher thresholds for specific groups.

At the bedside

  1. 1

    Red cells

    Hb < 7 g/dL for hospitalised and ICU patients including septic shock; < 7.5 for cardiac surgery; < 8 for orthopaedic surgery or pre-existing cardiovascular disease. Give 1 unit, then reassess.

  2. 2

    Acute MI

    MINT suggested a possible benefit of a liberal (Hb < 10) strategy in MI with anaemia; consider a higher threshold.

  3. 3

    Platelets

    Prophylactic < 10 × 10⁹/L (hypoproliferative); < 20 for CVC insertion; < 50 for LP or major non-neuraxial surgery; < 100 for neurosurgery/eye surgery or ICH; > 50 in active bleeding.

  4. 4

    Plasma

    Not for isolated raised INR without bleeding or before low-risk procedures; 15-20 mL/kg for bleeding with factor deficiency.

  5. 5

    Massive haemorrhage

    Use the massive transfusion protocol with balanced ratios (see trauma module); monitor Ca²⁺, temperature and viscoelastic tests.

  6. 6

    Bedside safety

    Two-person ID check, baseline obs; observe first 15 min closely; stop transfusion at first sign of a reaction.

Anaemia below threshold

Packed red blood cells

IV
Dose
1 unit then recheck Hb
Worked example
70 kg with Hb 6.4: 1 unit over 2-3 h → expected Hb ~7.4 g/dL

Thrombocytopenia

Platelet concentrate

IV
Dose
1 apheresis unit or 4-6 random-donor units
Worked example
70 kg: 1 SDP or 6 RDP; check 1-h post-count

Bleeding with coagulopathy

Fresh frozen plasma

IV
Dose
15-20 mL/kg
Worked example
70 kg: 1,050-1,400 mL ≈ 4-6 units

Acute transfusion reactions

ReactionKey featuresAction
Febrile non-haemolyticFever < 2 °C rise, no other signsStop, exclude haemolysis/sepsis, paracetamol; may restart
Allergic / anaphylaxisUrticaria; or hypotension, bronchospasm, angioedemaStop; antihistamine; adrenaline 0.5 mg IM for anaphylaxis
Acute haemolytic (ABO)Fever, loin pain, hypotension, haemoglobinuria, DICStop, keep line open, fluids, recheck ID, DAT, haemolysis screen, inform blood bank
TACODyspnoea, hypertension, raised JVP, pulmonary oedema within 12 hStop/slow, sit up, diuretic, oxygen/NIV
TRALIHypoxaemia, bilateral infiltrates within 6 h, often hypotension, no volume overloadStop, supportive (lung-protective ventilation), avoid diuretics, report donor
Septic (bacterial contamination)High fever, rigors, shock (especially platelets)Stop, culture bag and patient, broad-spectrum antibiotics
Red flag · call your senior now
Fever, hypotension and loin pain within minutes of starting blood: suspect ABO incompatibility - stop immediately.
Pitfall
Transfusing 2 units reflexively in stable patients: give single units and reassess.
Pitfall
Giving FFP to correct mildly raised INR before a central line.
Pearl
TACO is the commonest cause of transfusion-related death in many haemovigilance systems; watch fluid balance in elderly and cardiac patients.

References

  1. 1

    Carson JL, Stanworth SJ, Guyatt G, et al. Red blood cell transfusion: 2023 AABB international guidelines. JAMA 2023;330:1892-902.

  2. 2

    Holst LB, Haase N, Wetterslev J, et al. Lower versus higher hemoglobin threshold for transfusion in septic shock (TRISS). N Engl J Med 2014;371:1381-91.

  3. 3

    Carson JL, Brooks MM, Hebert PC, et al. Restrictive or liberal transfusion strategy in myocardial infarction and anemia (MINT). N Engl J Med 2023;389:2446-56.

  4. 4

    Kaufman RM, Djulbegovic B, Gernsheimer T, et al. Platelet transfusion: a clinical practice guideline from the AABB. Ann Intern Med 2015;162:205-13.

  5. 5

    Vlaar APJ, Dionne JC, de Bruin S, et al. Transfusion strategies in bleeding critically ill adults: a clinical practice guideline from the European Society of Intensive Care Medicine. Intensive Care Med 2021;47:1368-92.

  6. 6

    Kietaibl S, Ahmed A, Afshari A, et al. Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: second update 2022. Eur J Anaesthesiol 2023;40:226-304.

  7. 7

    Rossaint R, Afshari A, Bouillon B, et al. The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition. Crit Care 2023;27:80.

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Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.