FORT LEONARD WOOD, Mo. — A child with a rare blood disease; an adult injured in a vehicle accident; someone with cancer; and a warrior injured on the battlefield all have something in common. They all rely on caring individuals to donate blood to help them recover from their wounds and illnesses.

The Department of Defense needs about 400 units of blood every day just to meet operational requirements. If a catastrophe or mass casualty situation happens, that number goes up drastically. So, military officials rely on the Armed Services Blood Program to ensure an ample supply is available for any situation.

“It’s too late to donate blood when an emergency happens — people will need it immediately,” said Felix Ortiz-Plaza, Fort Leonard Wood Blood Donor Center quality assurance officer. “So, if you have your health, celebrate it by giving blood to those who are not as fortunate and to help us be ready for those ‘just in case’ situations.”

When these situations happen and someone needs a blood transfusion, one of the main steps in the process is knowing the individual’s blood type.

“Knowing what blood types are compatible with others when transfusing blood is very important,” Ortiz-Plaza said. “If a patient receives the wrong blood type, it can result in a transfusion reaction with symptoms ranging from a fever to kidney failure. At any rate, it will make the recipient very ill and could even cause death. That is why we test and cross-match blood products that will be transfused.”

Blood types fall into one of four blood groups: A, B, AB and O. Tiny markers known as antigens, which cover the cell’s surface, determine these blood groups.

An antigen is any substance that, when introduced into a body and recognized as foreign, will bring about an immune response. This might result in producing an antibody that will react specifically with that antigen.

When a donor gives a unit of whole blood, it is usually processed into two components: packed red blood cells and fresh frozen plasma, Ortiz-Plaza said. Packed red blood cells contain antigens and fresh frozen plasma contains antibodies.

How it works

Group A whole blood has A antigens and B antibodies. Group B whole blood has B antigens and A antibodies. Group AB blood has both A and B antigens and neither A nor B antibodies. Group O blood has neither A nor B antigens but has both A and B antibodies.

In addition to A and B antigens, blood also has a D antigen. The presence or absence of this antigen helps determine an individual’s exact blood type.

Individuals who have these antigens are known as Rh positive and individuals without them are Rh negative. The combination of an individual's blood group (A, B, AB, O) and the presence or absence of the Rh antigen, positive or negative, determines an individual's blood type.

“Knowing your blood type is very important whether you’re giving to someone else or having to receive it,” Ortiz-Plaza said. “Donors and recipients must have their blood types matched to make sure everyone is safe in the transfusion process. This is known as a cross match.”

That said, here’s some compatibility information to keep handy, courtesy of the Armed Services Blood Program.

(Photo Credit: U.S. Army) VIEW ORIGINAL

Group A blood: 40 percent of the American population

Type A positive and A negative donors have the second-most common blood type. About 34 percent of the population has A positive blood, and A negative donors represent about 6 percent of the population. Type A positive patients can receive A positive, A negative, O positive or O negative packed red blood cells. Type A negative patients can receive A negative and O negative packed red blood cells only. Type A negative donors can also provide red blood cells for the more scarce Type AB patients if necessary.

Group B blood: 11 percent of the American population

Type B positive and B negative donors have the more rare blood types. B positive donors make up 9 percent of the population while B negative donors are the second rarest at only 2 percent. Type B positive patients can receive B positive, B negative, O positive and O negative packed red blood cells. Type B negative patients can only receive B negative and O negative packed red blood cells. Type B negative donors can also provide red blood cells for the more scarce Type AB patients if necessary.

Group AB blood: 4 percent of the American population

Type AB positive and AB negative donors have the rarest blood types – AB positive, 3 percent of the population; AB negative, 1 percent. Despite that fact, they are "universal plasma donors” because anyone can receive Type AB plasma. For that reason, Type AB plasma is often used in emergency situations before a person's exact blood type can be determined. Type AB positive patients can receive packed red blood cells from all types. Type AB negative patients can only receive AB negative, A negative, B negative or O negative packed red blood cells.

Group O blood: 45 percent of the American population

Type O negative donors make up only 7 percent of the American population, but they are more useful than rare. These are the "universal donors” because anyone can receive O negative packed red blood cells. Type O negative red blood cells are often used in emergency situations before a person's exact blood type can be determined. Although they are the universal donor, type O negative patients can only receive type O negative packed red blood cells. Type O positive donors have the most common blood type. They represent about 38 percent of the American population. To put it in perspective, consider that about every third person you see walking down the street has O positive blood. Type O positive patients can receive O positive and O negative packed red blood cells only.

“No one ever expects to need blood, but the consequences can be deadly if it is needed and not available,” Ortiz-Plaza said. “Whether giving or receiving blood, knowing your blood type is important.”

Anyone wanting more information about donating blood or to make an appointment to donate should call 573.596.5385. The ASBP is the official blood collection agency for the Department of Defense, serving nearly 1.3 million military healthcare beneficiaries worldwide.

About the Armed Services Blood Program

Since 1962, the Armed Services Blood Program has served as the sole provider of blood for the United States military. As a joint operation, the ASBP collects, processes, stores and distributes blood and blood products to service members and their families worldwide. As one in four national blood collection organizations trusted to ensure the nation has a safe, potent blood supply, the ASBP works closely with our civilian counterparts by sharing donors on military installations where there are no military collection centers and by sharing blood products in times of need to maximize availability of this national treasure.