Serology is the branch of immunology that studies blood serum and other bodily fluids, focusing primarily on the detection of antibodies and antigens related to infections and immune responses.

• Antibodies (e.g., IgG, IgM) produced in response to specific pathogens
• Antigens from viruses, bacteria, or other microorganisms

• Diagnosing viral infections (e.g., HIV, HCMV, hepatitis)
• Monitoring immune status or past exposure
• Evaluating autoimmune diseases (e.g., lupus, Sjögren's)
• Assessing vaccine response

• IgM antibodies indicate recent or acute infection
• IgG antibodies suggest past exposure or long-term immunity