EDITORIAL SERIES ON METHODOLOGY 5 Radioimmunoassay, enzyme and non-enzyme-based immunoassays

The ability to quantify the amount of a specific protein in a complex sample has been a valuable addition to laboratory science, allowing thedevelopmentofdiagnostic tests, allergen detection in the food industry,andscreening for immunity. This is particularly important in anaesthesia, intensive care, and pain research for the quantification of mediators (cytokines, peptides, and analytes) involved in inflammation, pain, and other pathways. Immunoassays use the high specificity of antibodies, along with their enormous diversity, to target specific molecules of interest and analyse their concentration in a sample. The first immunoassay developed was described by Yalow and Berson1 in 1959.2 They used radiolabelled insulin to assess the concen-trationof insulin inhumanplasma,and thusdeveloped thefirst radioimmunoassay (RIA). In 1971, Engvail and Perlman