Learning objectives Describe how an Avidity ELISA work in the context of antibody binding. Explain what a chotropic agent is. Explain the purpose of each of these steps: Adhesive plastic ELISA plate. Coating the well with antigen protein. Blocking with bovine albumin. Plasma incubation which contains the antibody. Addition of increasing concentrations of a chaotropic agent in different wells. Detection antibody from another species (e.g. mouse anti-human IgG). HRP conjugation (joining) to detection antibody. Colourless substrate peroxidation to coloured product. Understand a chaotropic agent concentration vs absorbance curve and what it means.