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Calculators

Allowable Blood Loss

Estimated allowable blood loss before transfusion threshold.

ABL = EBV × (Hct_start − Hct_target) / Hct_avg
EBV
6,000mL
Allowable blood loss
2,000mL
Average Hct = 36%

ABL is a guide, not a transfusion trigger. Consider the patient's oxygen demand, comorbidities, ongoing losses, and dynamic markers (ScvO₂, lactate, hemodynamics).

References & Further Reading

  1. 1
    Textbook

    Gropper MA, Miller RD, Cohen NH, et al., eds. Miller's Anesthesia. 9th ed. Philadelphia: Elsevier; 2020.

  2. 2
    GuidelineOpen source

    Practice Guidelines for Perioperative Blood Management: An Updated Report by the American Society of Anesthesiologists Task Force. Anesthesiology. 2015;122(2):241-275.

Citations are provided to direct further study. Always check the most current edition of guidelines and society recommendations — the information in this chapter is a teaching summary, not primary source material.