Plasma Volume Calculator
Calculate blood plasma volume using hematocrit, weight, and height
Calculate Plasma Volume
Normal adult weight: 50-100 kg (110-220 lbs)
Normal range: Men 40-50%, Women 36-44%
Calculation Methods
Simple Method
TBV = 70 mL/kg (males)
TBV = 65 mL/kg (females)
Nadler's Equation
More accurate method using height and weight with gender-specific formulas
Lemmens Formula
BMI-adjusted calculation for better accuracy in different body types
Normal Ranges
Hematocrit
Men: 40-50%
Women: 36-44%
Plasma Volume
~55% of blood volume
~2500-3500 mL (adults)
Total Blood Volume
Men: ~5-6 L
Women: ~4-5 L
Clinical Applications
Blood donation planning
Fluid replacement therapy
Plasma exchange procedures
Surgical blood loss estimation
Drug dosing calculations
Understanding Plasma Volume
What is Blood Plasma?
Blood plasma is the liquid component of blood that makes up approximately 55% of total blood volume. It's primarily composed of water (95%) along with proteins, glucose, clotting factors, electrolytes, hormones, and waste products.
Plasma Components
- •Water: Up to 95% by volume
- •Proteins: 6-8% (albumin, globulins, fibrinogen)
- •Glucose: Primary energy source
- •Electrolytes: Na+, Ca2+, Mg2+, Cl-, etc.
Calculation Formula
Plasma Volume = TBV × (1 - Hematocrit)
Where TBV = Total Blood Volume and Hematocrit is expressed as a fraction
Clinical Significance
- Blood Donation: Ensures safe donation volumes
- Surgery: Estimates blood loss tolerance
- Fluid Therapy: Guides replacement strategies
- Drug Dosing: Affects medication distribution
Example Calculation
70 kg woman with 45% hematocrit:
TBV = 70 × 65 = 4,550 mL
PV = 4,550 × (1-0.45) = 2,503 mL
Plasma Donation
Understanding plasma volume helps determine safe donation amounts and recovery times for plasma donors.
Medical Applications
Used in transfusion medicine, critical care, and surgical planning for optimal patient management.
Important Considerations
- • Plasma volume varies with hydration status and posture
- • Pregnancy and certain medications can affect calculations
- • Individual variation exists despite standardized formulas
- • Serial measurements may be more valuable than single calculations
- • Always consider clinical context when interpreting results