Work out blood loss estimate instantly with clear inputs, formula shown and shareable results.
Estimates blood loss from the fall in haematocrit relative to the patient's estimated blood volume.
Blood loss from haematocrit
EBV = weight x mL/kg; loss = EBV x (starting Hct - current Hct) / starting Hct
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
Haematocrit falls only after fluid shifts or resuscitation dilute the remaining blood, which lags behind rapid bleeding.
About 70 mL/kg in adult men, 65 in women, 80 in infants and 85 to 90 in neonates.