Allowable Blood Loss (ABL) Calculator

Your details

Selects the standard estimated blood volume (EBV) factor for this patient population.
Patient body weight used to calculate estimated blood volume.
Choose whether you have hematocrit or hemoglobin values.
The patient's hematocrit on the morning of surgery.
%
The lowest hematocrit you are willing to accept before transfusing (typically 21-30%).
%
Allowable Blood LossAdequate margin
2,494mL

Maximum blood loss before transfusion threshold is reached

Estimated Blood Volume5,250mL
Fraction of EBV47.5%
EBV factor used75mL/kg
47.5% %
Very narrow<15%Moderate margin15%-25%Adequate margin25%-50%Large margin50%+

Maximum allowable blood loss is 2494 mL (47.5% of EBV).

  • This patient's estimated total blood volume is 5250 mL.
  • The allowable loss (2494 mL) represents 47.5% of that total.
  • Starting at 40.0% hematocrit, transfusion is indicated when hematocrit/hemoglobin falls to 21.0% hematocrit.

Next stepAdequate margin, but continue tracking estimated blood loss against this threshold throughout the procedure.

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