Pediatric Blood Transfusion Volume Calculator

Created by Małgorzata Koperska, MD
Reviewed by Bogna Szyk and Aleksandra Zając, MD
Based on research by
Patrick Davies, Simon Robertson, Shilpa Hegde, Rosemary Greenwood, Edwin Massey, Peter Davis Calculating the required transfusion volume in children Transfusion (Jan 2007)
Last updated: Aug 02, 2022

Our pediatric blood transfusion volume calculator uses a formula for blood transfusion volume described in an article titled Calculating the required transfusion volume in children written by Drs. Davies P, Robertson S, Hegde S, Greenwood R, Massey E, and Davis P from the Paediatric Intensive Care Unit, Bristol Royal Hospital for Children.

This calculator estimates the blood transfusion volume for children required to achieve the aimed hemoglobin increment.

We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace a professional doctor's assessment. If any health condition bothers you, consult a physician.

Why do I need a blood transfusion volume calculator?

Estimating the blood transfusion volume for adult patients is very simple. One unit of packed red blood cells usually raises the hemoglobin concentration by 1 g/dl or hematocrit by 3%. This transfusion practice is imprecise, but it's widely recognized and applied.

For children, though, it's understandable that a calculation is needed. Their total blood volume can vary substantially depending on their weight and age. The pediatric transfusion volume of blood required for the hemoglobin increment of 1 g/dL administered to an infant is considerably lower than that needed for an adolescent.

Remember to adjust the dosage of medicines for children. You may find our ibuprofen calculator and paracetamol dosage calculator useful.

Which values do I need to estimate the blood transfusion volume for children?

The values required to calculate the blood volume for transfusion are:

  • The patient's weight in kilograms;
  • Hematocrit (of the transfused blood) in %; and
  • The desired increment in hemoglobin in g/dL.

Hematocrit is the percentage of the volume of red blood cells in the blood, with normal value ranges 42-65% for new born babies in the first month, 33-55% in the second month, 28-41% from the third to the sixth month, and 31-41% after the sixth month of life.

For children between 1 and 5 years of age, the norm is 31-44%, and after the fifth birthday, it's roughly 37-48% for males and 34-44% for females.

The increment in hemoglobin is the difference between the patient's hemoglobin and the aimed level. Transfusion is usually used to maintain a blood hemoglobin concentration above 10 g/dL.

What's the formula for blood transfusion volume?

The formula for pediatric blood transfusion volume (BTV) was developed by Drs. Davies P, Robertson S, Hegde S, Greenwood R, Massey E, and Davis P and described in the article Calculating the required transfusion volume in children is as follows:

BTV (mL) = weight (kg) × aimed increment in hemoglobin (g/dL) × 3 / hematocrit

where hematocrit is expressed as decimal.

🔎 Are you searching for a calculator to accurately estimate when you can donate blood after a donation? Check out our blood donation due-date calculator.

Małgorzata Koperska, MD
Desired hemoglobin increment
Transfusion blood volume
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