Antigen

A substance that is foreign to the body which causes the immune system to produce antibodies to fight it.

Antibody

A protein that is produced by the body in response to invasion or exposure to an antigen.  Red cell antibodies usually occur in response to and following a blood transfusion or mixing of mother and baby's blood during pregnancy.

Blood Transfusion

A term used when a patient is treated with the infusion of blood or blood products.

Coagulation Factor Deficiency

A term referencing any form of hemophilia or other clotting problems.

Hemophilia

A disease acquired or inherited which causes a person to be deficient in "factors" (proteins) in the blood which aid in clotting.

Plasma

The watery fluid in which all blood cells are suspended, unlike with donating blood, a healthy person can donate plasma up to twice a week without ill effects.  A person's antibodies can then be extracted from their plasma.

Rh

A "factor" (protein) attached to the red cells of some people which helps distinguish their blood from the blood of others.

Rh Disease of the Newborn

Also known as hemolytic disease of the newborn, it occurs when there is a mixing of the baby's and mother’s blood and the two are incompatible. The mother's immune system responds by building antibodies to RhD-positive red blood cells which, in the next pregnancy, will attack and destroy the baby's red blood cells if they are RhD-positive.

Rh Immune Globulin

An immunization administered to Rh negative women during pregnancy and following delivery which prevents Rh disease of the newborn. This immunization is manufactured using donor's Rh antibodies.