General Information for Blood

GENERAL INFORMATION FOR BLOOD - GROUP

One unit of blood can be separated into several components, including red blood cells, plasma and platelets. Red blood cells carry oxygen to the body's organs and tissue. Plasma is a pale yellow mixture of water, salts and proteins, including solvable clotting factors; plasma is 90 percent water and constitutes 55 percent of blood volume. Platelets are small blood cells that initiate blood clotting, controlling bleeding.

Every three seconds, someone needs blood. Blood fights against infection and helps heal wounds, keeping you healthy. Anemic patients need blood transfusions to increase their iron levels. Cancer, transplant and trauma patients and patients undergoing open-heart surgery require platelet transfusions to survive. People who have been in car accidents and suffered massive blood loss can need transfusions of 50 units or more of red blood cells.

The average bone marrow transplant requires 120 units of platelets and about 20 units of red blood cells. Severe burn victims can need 20 units of platelets during their treatment. Children being treated for cancer, premature infants, and children having heart surgery need blood and platelets from donors of all types.

Apheresis (ay-fur-ee-sis) is a special kind of blood donation that allows a donor to give specific blood components, such as platelets. Platelets must be used within five days of collection, hence blood donations are especially needed around 3-day weekends. Red blood cells must be used within 42 days. Plasma can be frozen and used for up to a year.

Blood makes up about 7 percent of your body's weight, and the average adult has 10 pints of blood in his or her body. Since a pint is pound, you lose a pound every time you donate blood.