Also known as Blood Serum.
The clear, watery fluid that separates from clotted blood. Unlike blood plasma, serum does not contain any fibrinogen or blood clotting agents. However, because serum contains antibodies and anti-toxins, it may be taken and purified from a human or animal recovering from a disease such as hepatitis or diphtheria, and then injected into the bloodstream of another person to provide what is known as passive immunity. This technique may be used when there is a high risk of infection and insufficient time for the body to develop its own immune response, or to reduce the symptoms of ongoing or immunosuppressive diseases.
