# Plasma Volume Calculator

Determines total blood, RBC and plasma values based on patient criteria, hematocrit, height and weight.

This calculator estimates based on patient criteria, hematocrit, height and weight three important blood volumes:

• Plasma volume – the liquid that holds the blood cells in whole blood in suspension;
• RBC volume – the red blood cell volume component of whole blood;
• Total blood volume – total amount of blood circulating in the body.

For total blood volume, the formulas used depend on patient characteristics:

 Patient Formula Preterm neonate 100 mL/kg Term neonate 85 mL/kg Infant aged 1-4 months 75 mL/kg Child <25 kg (55 lbs) 70 mL/kg Adults and children ≥25 kg Male = [ 0.3669 × (height, m)3 + 0.03219 × (weight, kg) + 0.6041]Female = [ 0.3561 × (height, m)3 + 0.03308 × (weight, kg) + 0.1833]

`RBC volume = Total blood volume, mL × hematocrit / 100`

`Plasma volume = Total blood volume, mL × (1 – hematocrit / 100`)

Patient Type
Hematocrit
Weight
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Steps on how to print your input & results:

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

## Blood volume determinations

There are three important blood volumes that can be estimated based on patient criteria, hematocrit, height and weight:

• Plasma volume;
• RBC volume;
• Total blood volume – total amount of blood circulating in the body.

Plasma volume (which accounts for about 55% of the body’s total blood volume) is the liquid that holds the blood cells in whole blood in suspension. Blood plasma is separated by centrifugation in an anticoagulant solution. Blood plasma volume may be expanded by or drained to extravascular fluid when there are changes in Starling forces across capillary walls. Blood serum represents blood plasma deprived of clotting factors.

`Plasma volume = Total blood volume, mL × (1 – hematocrit / 100)`

RBC volume represents the quantity of the red blood cells component of whole blood and is derived from hematocrit and total blood volume:

`RBC volume = Total blood volume, mL × hematocrit / 100`

Total blood volume is estimated depending on patient characteristics:

 Patient Formula Preterm neonate 100 mL/kg Term neonate 85 mL/kg Infant aged 1-4 months 75 mL/kg Child <25 kg (55 lbs) 70 mL/kg Adults and children ≥25 kg* Male = [ 0.3669 × (height, m)3 + 0.03219 × (weight, kg) + 0.6041]Female = [ 0.3561 × (height, m)3 + 0.03308 × (weight, kg) + 0.1833]

*For this category, the total blood volume Nadler’s formulas are used.

## References

Nadler SB, Hidalgo JH, Bloch T. Prediction of blood volume in normal human adults. Surgery. 1962;51(2):224-32.

Sharma R, Sharma S. Physiology, Blood Volume. Treasure Island (FL): StatPearls Publishing; 2020 Jan.

Specialty: Cardiology

System: Cardiovascular

Article By: Denise Nedea

Published On: May 15, 2020

Last Checked: May 15, 2020

Next Review: May 15, 2025