Red Cell Exchange Volume
Estimate red cell exchange units from body weight, HbS percentage, and configurable blood volume assumptions.
Red cell exchange volume
Estimates packed red cell units using patient weight, HbS, and the supporting blood-volume assumptions behind the bedside rule. If HbS is unknown, the calculation defaults to 100%.
Pre-exchange HbS
If not available, the tool assumes 100% and estimates a full one-volume exchange requirement.
Weight used
70 kg
HbS used
80%
One-volume exchange
7.42 units
Derived exchange assumptions
Estimated blood volume
4,900 mL
Estimated red cell mass
1,470 mL
Red cell content per unit
198 mL
One-volume replacement
7.42 units
Method summary
This planner starts with the patient's estimated blood volume, converts that to an approximate red cell mass, and divides by the red cell content of one packed unit to estimate a one-volume exchange.
The HbS-adjusted bedside estimate then scales that one-volume exchange by the pre-exchange HbS fraction. A 70 kg patient at 80% HbS yields 5.94 raw units, which this tool rounds to 6.
Use this as a planning aid and pair it with local exchange protocols, the patient's current clinical context, target post-RCE HbS, and product availability.