radial immunodiffusion


gel dif·fu·sion pre·cip·i·tin tests in one di·men·sion

precipitin tests in which antigen solution and antibody incorporated in agar are layered in tubes, permitting effective diffusion in the vertical dimension; the antibody-containing agar may be overlaid directly with antigen solution (single [gel] diffusion in one dimension).

radial immunodiffusion

Abbreviation: RID
A means of measuring the amount of antigen in a sample in which a solution containing the antigen is dropped into a gel evenly impregnated with antibody. The diameter of the ring that precipitates around the solution varies directly with the amount of antigen in the solution. See also: immunodiffusion