The body will replace the fluids of the donated blood in just 24 hours. The red blood cells will be replaced in about 6 to 8 weeks. After 3 months, a person can choose to donate again.
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.