The total volume of the blood plasma in the circulatory system
The blood is comprised of plasma and different cellular components. The various types of cells in the blood include the red blood cells, white blood cells, and platelets. These cells are suspended in the pale yellow liquid component of the blood called plasma. The plasma is the intravascular fluid comprised of water, dissolved proteins, glucose, clotting factors, electrolytes, hormones, and carbon dioxide.
Blood volume pertains to the volume of blood in the circulatory system. In general, the blood volume of an adult is about five liters. It is calculated by the formula: plasma volume / (1 – hematocrit). The plasma volume can be measured by indicator dilution techniques.
The blood plasma of an average human being is about 55% of the total blood volume of the body.1 A typical blood plasma volume in males is about 39 mL/kg of the body weight whereas in females it is about 40 mL/kg. A high blood plasma volume could indicate a disease in the liver and spleen or a vitamin C deficiency. Low plasma volume is observed in conditions such as shock, dehydration, and Addison’s disease.2
1 O’Neil, D. (1999). “Blood Components”. Palomar College. Retrieved from http://anthro.palomar.edu/blood/blood-components.htm
2 plasma volume. (n.d.) Mosby’s Medical Dictionary, 8th edition. (2009). Retrieved from http://medical-dictionary.thefreedictionary.com/plasma+volume