Blood Transfusion Volume Calculator for Dogs & Cats (pRBC)
Volume of packed red blood cells needed to reach a target PCV, from the recipient's PCV, the unit's PCV and blood volume.
Results are calculated in your browser. Always double-check before administering and use your clinical judgement.
How it is calculated
Volume (mL) = ((desired PCV − recipient PCV) ÷ unit PCV) × blood volume (mL/kg) × body weight (kg). Blood volume: 80–90 mL/kg in dogs and 40–60 mL/kg in cats [1].
A test dose of about 0.25 mL/kg over 15 minutes is given before the full transfusion [1].
Worked example
Dog 20 kg, PCV 12 → 25 %, unit PCV 60 %, 90 mL/kg: (13 ÷ 60) × 90 × 20 = 390 mL.
Frequently asked questions
How do you calculate how much blood to transfuse?
Packed RBC volume = ((desired PCV − recipient PCV) ÷ unit PCV) × blood volume × body weight, with blood volume 80–90 mL/kg in dogs and 40–60 mL/kg in cats [1].
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References
For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.