serólógía

Serology is the branch of immunology that studies serum and the immune responses reflected in blood serum, with a focus on the detection and measurement of antibodies and antigens. It is used to diagnose infectious diseases, determine immune status after infection or vaccination, and support a range of clinical and research applications.

The core principle of serology is antigen–antibody interaction. Serological tests detect specific antibodies produced in response to pathogens (such as IgM and IgG) or identify antigens from pathogens. Serology can indicate a current infection (evidence of IgM or rising antibody titers) or past exposure (IgG), and antibody levels can be quantified.

Common techniques include enzyme-linked immunosorbent assay (ELISA), Western blot, immunofluorescence assays, agglutination, precipitation, and rapid lateral flow tests. These methods vary in sensitivity, specificity, and suitability for point-of-care use, and are often selected based on clinical context and available resources.

Applications of serology span infectious disease diagnosis (for example, HIV, hepatitis B and C, syphilis), blood typing and transfusion medicine, transplantation compatibility testing, autoimmune disease screening (autoantibodies), and evaluation of vaccine responses and population seroprevalence.

History of serology traces to work in the late 19th and early 20th centuries, including Karl Landsteiner’s discoveries related to blood groups and Behring and Kitasato’s early antibody-based therapies, which laid the foundation for modern serological diagnostics and immunology.

Limitations and considerations include cross-reactivity leading to false positives, timing of sample collection relative to infection (window period), and potential false negatives. Confirmatory testing and clinical correlation are often required.