Serology primarily examines the presence of what in serum?

• A. Antibodies
• B. Antigens
• C. Enzymes
• D. Hormones

Answer: (A)

Serology centers on the immune components in blood serum, with antibodies being the main focus. These immunoglobulins are produced by B cells in response to infection or vaccination, and their presence in serum serves as a marker of exposure or immune status. Tests that detect antibodies (such as in indirect ELISA or immunofluorescence assays) help determine whether someone has mounted a humoral response or has been exposed to a pathogen, and they can also give clues about timing (for example, IgM suggests recent exposure while IgG indicates past exposure or longer-term immunity). While some serology tests can detect antigens, the classic aim is to identify antibodies in the serum. Enzymes and hormones are measured in other kinds of assays and are not the primary focus of serology.