When giving blood, approximately 470mL of blood will be donated (7% - 8% of the blood volume of an average adult, i.e. approx. 1.5 cans of soft drink), plus 15mL for test samples.
Plasma, which is 90% water, constitutes about 55% of blood volume. Plasma contains:
Plasma serves a variety of functions, from maintaining a satisfactory blood pressure and volume to supplying critical proteins for blood clotting and immunity. It also serves as the medium of exchange for vital minerals such as sodium and potassium.