Plasma is a pale yellow mixture of water, proteins and salts. One of the functions of plasma is to act as a carrier for blood cells, nutrients, enzymes and hormones. Plasma can be stored in a frozen state for up to one year. It is used to treat bleeding disorders and burn patients. Whole blood and plasma donations are used in hospitals as transfusable blood components, but any plasma not needed as a transfusable component is provided to plasma fractionators for use in producing medicines used to treat Ig deficiency.