1. What is Plasma Volume?

Plasma volume is the fluid portion of blood that remains after removal of the cellular elements. It's calculated by subtracting the packed cell volume (hematocrit) from the total blood volume.

2. How Does the Calculator Work?

The calculator uses the plasma volume formula:

Where:

• Blood Volume — Total blood volume in milliliters (mL)
• Hematocrit — Percentage of blood volume occupied by red blood cells (%)

Explanation: The formula calculates the liquid portion of blood by subtracting the cellular component (represented by hematocrit) from the total blood volume.

3. Importance of Plasma Volume Calculation

Details: Plasma volume measurement is important for assessing blood composition, diagnosing conditions like dehydration or overhydration, and guiding fluid therapy in critical care.

4. Using the Calculator

Tips: Enter blood volume in mL and hematocrit as a percentage (0-100%). Both values must be valid (blood volume > 0, hematocrit between 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal plasma volume?
A: Normal plasma volume is approximately 40-50 mL/kg in adults, but varies with body size and composition.

Q2: How is blood volume typically measured?
A: Blood volume can be estimated using formulas based on weight and height or measured directly using indicator dilution techniques.

Q3: Why is hematocrit expressed as a percentage?
A: Hematocrit represents the proportion of blood volume occupied by red blood cells, making percentage the most intuitive unit.

Q4: Are there limitations to this calculation?
A: This assumes normal blood composition. Conditions like polycythemia or severe anemia may affect accuracy.

Q5: When is plasma volume measurement most useful?
A: Particularly valuable in critical care, burns, shock, and conditions with significant fluid shifts.