periodic acid Schiff stain
(Science: technique) A histochemical technique based on periodic acid oxidation of a substance containing the 1,2-glycol grouping.
It is used for staining carbohydrates as the resulting dialdehyde reacts with Schiff reagent to form a coloured product.
Substances that can be demonstrated include carbohydrates, mucins, cartilage matrix, collagen, reticulum, basement membranes, fibrin, thyroid colloid, amyloid, glomerular hyaline deposits, and a number of other secretions or tissue constituents.
Also used in for staining gels on which glycoproteins have been run.
See: periodic acid Schiff reaction
Synonym: pAS stain.