Antibody tests can detect the presence of antibodies in the blood that
Antibodies, also known as immunoglobulins (Ig), are specialized proteins that bind to a uniquely shaped object—called an antigen—that is found on the surface of a pathogen. These pathogens can be things such as bacteria or viruses.
with a fitted molecular shape—and then either destroys the pathogen or tags it so other immune cells will recognize it.
