Transfusion: When & How Much

Blood, Clots & Transfusion · ICU Decoded chapter 46 · Locked — free with a referral

By Dr Javed Akhtar · Last reviewed 3 October 2026

Cited to AABB 2023.

Key points

Stay restrictive: transfuse at Hb 70 g/L (80 with cardiovascular disease or after cardiac surgery; ≥100 may be reasonable in acute MI); platelets <10 for prophylaxis, <50 when bleeding; plasma treats bleeding/procedures, never volume.
Give cryoprecipitate when fibrinogen is <1.5 g/L; transfuse platelets before LP only below 20×10⁹/L, and before a central line at a compressible site only below 10 (AABB/ICTMG 2025).
Stop the transfusion for reactions: TRALI (ARDS picture, supportive) vs TACO (diurese) vs hemolytic (fluids, DIC watch).
Massive transfusion brings hypocalcemia from citrate, hyperkalemia, and hypothermia; monitor and replete.

Investigations

First tests: Clinical assessment and product/patient checks, Full blood count.

Only if indicated: Blood group and crossmatch, Blood bank reaction panel, Blood cultures, Chest X-ray.

Repeat monitoring: Full blood count.

Management pathways in this chapter

Managing an Acute Hemolytic Reaction

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