What it does
Estimates blood volume and a blood-loss amount from a study factor and hematocrit values supplied in a problem. It does not choose a transfusion threshold.
The formulas
EBV = weight kg × selected factor in mL/kg. The tool offers these study factors: adult 70, child 75, infant 80, term neonate 85 and preterm neonate 95. blood-loss estimate = EBV × (starting Hct − supplied minimum Hct) ÷ starting Hct.
Worked example
For a 70 kg adult using the 70 mL/kg study factor and hematocrit values of 40% and 30%: EBV = 70 × 70 = 4900 mL. The blood-loss estimate is 4900 × (40 − 30) ÷ 40 = 1225 mL.
Good to know
Blood-volume factors and blood-loss models vary by age, body composition and reference. Use the model supplied by your study question. This estimate does not make a transfusion decision.
Study calculations only, not dosing recommendations. Real medication orders and administration require the appropriate clinical checks and facility protocol.
Open the interactive calculator