Cool Blood Facts

Blood Shelf Life

The blood supply must be replaced regularly to keep a current inventory of fresh blood and blood products. Blood products are refrigerated and have a shelf-life of:

• Ten years for source plasma
• One year for fresh frozen plasma
• Forty-two days for red blood cells
• Thirty-five days for whole blood
• Five days for platelets

Blood

Every minute of every day, someone in America needs blood. Much of the blood that is transfused every year is done under emergency or trauma situations. In the US, hundreds of thousands of people each year receive blood components or blood products following accidents, during surgery or for cancer treatments, burn therapy, hemophilia and other blood-related diseases.

• The average amount of blood in one person is 10.5 pints
• There are approximately 450 ml of blood in a unit
• On average, 4.6 units of blood are required per patient

Blood | Plasma | Platelets

Blood is comprised of several components. These components may be transfused separately or together to treat various conditions. Each donation of whole blood is separated into four main components:

• Red Blood Cells carry oxygen to tissues and are responsible for removal of carbon dioxide through the lungs.
• White Blood Cells protect the body from infection; however, they often carry viruses and bacteria. This is why these cells are removed in a process called leukoreduction to protect recipients from side-effects.
• Platelets provide the basis for clotting that helps control bleeding.
• Plasma is a liquid containing many of the body's proteins that help fight infection and help clotting. It distributes nutrients to tissues and transports waste products to the lungs, liver and kidneys, which expel them. Plasmapheresis yields twice the plasma as a whole blood donation.

Types & Rh System

Everyone's blood has a combination of elements from the different systems that classify blood. Two of these blood group systems are the ABO system and Rh system. The group you belong to depends on the presence or absence of proteins and sugars called antigens on the surface of your blood cells as well as the proteins called antibodies in the watery part of your blood. Not all blood types are compatible.

• There are four major blood groups A, O, B, and AB divided into Rh Positive and Rh Negative types: A (Rh Positive); A (Rh Negative); O (Rh Positive); O (Rh Negative); B (Rh Positive); B (Rh Negative); AB (Rh Positive); and, AB (Rh Negative).
• The most common blood type in Canada is O Rh Positive (approximately 39 per cent of Canadians have O Rh Positive blood). The rarest blood type is AB Rh Negative (only about one per cent of Canadians have AB Rh Negative blood). All blood types are needed to meet the needs of patients for blood and blood products.

People with O Rh Negative blood are considered universal donors because patients of all blood types can receive O Rh Negative blood.

Blood Types and Patient/Donor Compatibilities

Understanding Blood Antigens

At the genetic level, each person has two genes that determine his/her ABO blood type. The two genes carried by an individual are passed on from his/her parents. Although each parent also has two genes, they both contribute only one. This process of combining genes, one from each parent, can sometimes lead to children with different blood types than their parents. To discover the possible blood types of potential offspring, it is necessary to know the two genes of each of the parents.

A person with type A blood could have two A genes or one A gene and one O gene. Likewise, type B blood can result from a person with either two B genes or one B and one O gene. Type AB blood only occurs in a person with both A and B genes. People with type O blood have two O genes.