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.