- Enzyme-Linked Immunosorbent Assay; - Immunoassay utilising antibodies linked to enzymes for detection by colour change; - Evolved from RIA in the 1960s; - Antibody or analytebeing detected is absorbed to a solid surface, meaning unbound materials can be washed away with ease; - With time, more techniques were developed and ELISA is now used to describe any assay where a molecule is absorbed on a solid phase.