The most important of several blood group systems for typing human blood, based on the presence or absence of two antigens (A and B) on the surface of red blood cells. Blood types are A, B, AB, and O.

Transfusion of blood from a person other than the recipient, (i.e., NOT autologous). Same as homologous.

Condition in which the red cell content of the blood is below normal limits. Most common cause is a deficiency of iron, an element necessary for the formation of hemoglobin.

A protein produced by the immune system in response to a specific foreign substance (antigen) that attempts to eliminate the foreign substance from the body.

A protein or carbohydrate substance that is recognized by the body as foreign that stimulates an immune response.

An automated method of separating platelets, plasma, or red blood cellsfrom the donor's blood and returning all but that component to the donor. Also known as Apheresis Blood Collection, or ABC.

From auto (self) and logos (relation), it is a blood donation you give for your own surgery or medical needs.

The site of blood cell production, found within bone cavities.

Complex chemical present in all animal fats and widespread in the body and nerve fiber sheaths.

Component of blood obtained by freezing and thawing plasma. Useful in replacing some clotting factors in patients missing them congenitally or because of operation or trauma.