Transfusion threshold
Formal Definition
The hemoglobin or platelet value below which transfusion is indicated; evidence-based thresholds recommend transfusing packed red blood cells (pRBCs) when Hgb <7 g/dL in most stable hospitalized patients (restrictive strategy), with higher thresholds (<8 g/dL) for patients with active cardiac disease or acute coronary syndromes.
How It's Used on the Ward
"What is the transfusion trigger?" or "transfuse for a 7" — shorthand for the hemoglobin cutoff guiding the decision to give blood.
Example
""Post-op hemoglobin 6.8 in an otherwise stable 45-year-old — she is symptomatic with tachycardia and fatigue. Transfusing 1 unit pRBC and rechecking in 4 hours. Expected bump: 1 unit raises Hgb ~1 g/dL in a 70 kg adult.""
Clinical Context
Restrictive transfusion strategy (Hgb <7) is supported by TRICC and TRISS trials — equivalent or better outcomes vs liberal (Hgb <10), with fewer complications (transfusion reactions, TACO, TRALI, infection). Exception: ACS/active cardiac ischemia — use Hgb <8 threshold. Platelet transfusion thresholds: <10K for prophylaxis in non-bleeding; <50K before invasive procedures/surgery; <100K for neurosurgery/ophthalmologic procedures. FFP: given for active bleeding with coagulopathy (INR >1.5–2.0) or before procedures in coagulopathic patients. Always consider: is the patient symptomatic? Is there active bleeding? What is the underlying cause?