Radial immunodiffusion

Radial immunodiffusion (RID) or Mancini method, Mancini immunodiffusion or single radial immunodiffusion assay, is an immunodiffusion technique used in immunology to determine the quantity or concentration of an antigen in a sample. Antibody is incorporated into a medium such as an agar gel. The antigen is then placed in a well that is punched out of the medium while the medium is on a microscope slide or in an open container, such as a Petri dish. The slide or container is then covered or closed to prevent evaporation.