<prompt> Which one of the following stains is specific forAmyloid?Periodic Acid schif PASAlzerian redCongo redVon - Kossa  <response>: Ans. is c i.e., Congo Red To differentiate amyloid from other hyaline deposits eg. Collagen and fibrin, a variety of histochemical techniques are used, of which the most widely used is Congo Red - Robbins 7e p. 259 Staining for Amyloid Congo red : It is the most widely used specific stain for amyloid. Iodine staining : It is used for unfixed specimen or histological section. Amyloid stains mahogany brown and if sulfuric acid is added, it turns violet. Thioflavin T and S give secondary immunoflurescence with ultraviolet light. Thioflavin T is more useful for demonstrating juxtalomerular apparatus of the kidney. Metachromatic stains like crystal violet and methyl violet give rose pink appearance. Amyloid is PAS positive. 