periodic acid-Schiff
adjective
\ -ˈshif
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Medical Definition of periodic acid-Schiff
: relating to, being, or involving a reaction testing for polysaccharides and related substances in which tissue sections are treated with periodic acid and then Schiff's reagent with a reddish violet color indicating a positive test caused by the reaction with Schiff's reagent of aldehydes formed by the oxidation of hydroxyl groups on adjacent carbon atoms or of adjacent hydroxyl and amino groups