[rə′mōn ‚fläk·yə′lā·shən ‚test] (immunology) A method of standardizing antitoxins; a toxin-antitoxin flocculation that is a precipitin reaction in which the end point is the zone of optimal proportion; that is, the zone in which there is no uncombined antigen or antibody.MedicalSeeRamon, Gaston