Immunological assays are laboratory tests used to detect and measure the presence of specific antibodies or antigens in a sample, such as blood or tissue. These assays rely on the principle of immunology, which studies the immune system's response to foreign substances. Common types include enzyme-linked immunosorbent assays (ELISA) and Western blotting, each serving different diagnostic purposes. These tests are essential in various fields, including clinical diagnostics, vaccine development, and research. They help identify infections, autoimmune diseases, and allergies by providing valuable information about the immune response. Overall, immunological assays play a crucial role in understanding health and disease.