Blood

More than 4.5 million patients need blood transfusions each year in the U.S. and Canada.

43,000 pints: amount of donated blood used each day in the U.S. and Canada.

Someone needs blood every two seconds.

Only 37 percent of the U.S. population is eligible to donate blood – less than 10 percent do annually**.

About 1 in 7 people entering a hospital need blood.

One pint of blood can save up to three lives.

Healthy adults who are at least 17 years old, and at least 110 pounds may donate about a pint of blood—the most common form of donation—every 56 days, or every two months, depending on iron levels. Females receive 53 percent of blood transfusions; males receive 47 percent.

94 percent of blood donors are registered voters.

Four main red blood cell types: A, B, AB and O. Each can be positive or negative for the Rh factor. AB is the universal recipient; O negative is the universal donor of red blood cells.

Dr. Karl Landsteiner first identified the major human blood groups – A, B, AB and O – in 1901.

One unit of blood can be separated into several components: red blood cells, plasma, platelets and cryoprecipitate.

Red blood cells carry oxygen to the body’s organs and tissues.

Red blood cells live about 120 days in the circulatory system.

Platelets promote blood clotting and give those with leukemia and other cancers a chance to live.

Plasma is a pale yellow mixture of water, proteins and salts.

Plasma, which is 90 percent water, makes up 55 percent of blood volume.

Healthy bone marrow makes a constant supply of red cells, plasma and platelets.

Blood or plasma that comes from people who have been paid for it cannot be used to human transfusion.

Granulocytes, a type of white blood cell, roll along blood vessel walls in search of bacteria to engulf and destroy.

White cells are the body’s primary defense against infection.