Expected Hemoglobin and Hematocrit Increase After 10ml/kg RBC Transfusion in Pediatrics
A transfusion of 10 ml/kg of packed red blood cells should increase hemoglobin by approximately 20 g/L (2 g/dL) in pediatric patients. 1
Hemoglobin Increase
- The standard expected increase is 20 g/L (2 g/dL) per 10 ml/kg of RBCs transfused 1
- This guideline is consistent across multiple Association of Anaesthetists guidelines from both 2016 and 2025 1
- Blood should be prescribed by volume (ml/kg) rather than by units in pediatric patients to ensure accurate dosing 1
Hematocrit Increase
- The expected hematocrit increase is approximately 6% per 10 ml/kg of RBCs transfused 1
- This is derived from the hemoglobin increase using the standard conversion (Hct = Hb × 3) 2
- Research data confirms that with UK standard hematocrit of packed cells at 0.6, a 10 ml/kg transfusion produces a 2 g/dL hemoglobin increment 2
Important Clinical Considerations
Factors that may modify the response:
- Lower pre-transfusion hemoglobin levels are associated with greater hemoglobin increases per unit transfused 3
- The hematocrit of the RBC unit itself affects the calculation; the formula accounts for this: weight (kg) × desired Hb increment (g/dL) × 3 / (Hct of RBC unit) 2
- Post-transfusion hemoglobin measured at 1 hour is equivalent to that measured at 7 hours, so early assessment is reliable 2
Critical safety points:
- Children have higher rates of serious adverse transfusion events compared to adults, requiring careful monitoring 1
- Avoid hypervolemia by carefully calculating volumes, especially in smaller children 2
- Neonates require CMV-negative blood components and have different blood volumes (70-100 ml/kg) 1
- Children are at particular risk for electrolyte imbalance and hypothermia during rapid transfusion 1
Practical Application
For a typical calculation: