Serological assays refer to a group of laboratory tests that detect the presence of specific antibodies or antigens in a person's blood serum. These tests are commonly used in medical diagnostics, infectious disease screening, and immunological research. Serological assays can help identify past or current infections, autoimmune disorders, and certain types of cancers. They are often performed using techniques such as enzyme-linked immunosorbent assay (ELISA), Western blot, or rapid diagnostic tests. Overall, serological assays play a crucial role in the field of immunology and are vital for understanding and diagnosing various diseases.