Allowable Blood Loss
Maximum allowable blood loss from weight and haemoglobin.
EBV = weight × blood-volume factor. ABL = EBV × (initial − minimum Hb) ÷ initial Hb. Education only — transfusion thresholds and blood-volume estimates must follow local protocol and the clinical picture.
Maximum allowable blood loss
2250
mL
Estimated blood volume
5250 mL
75 mL/kg × 70 kg
Maximum allowable blood loss
Allowable blood loss (ABL) estimates how much blood a patient can lose before reaching a minimum acceptable haemoglobin, helping plan transfusion and fluid strategy in surgery.
How it is calculated
Estimated blood volume (EBV) = weight × a blood-volume factor (about 75 mL/kg adult male, 65 female, 70 child, 80 infant). ABL = EBV × (initial − minimum Hb) ÷ initial Hb.
When it helps
Useful before liposuction, large flap or body-contouring surgery to set a transfusion trigger and guide intraoperative fluid replacement.
Education only — an estimate; transfusion decisions depend on the whole clinical picture and local protocol.