<prompt> The stain used to detect amyloid is?Grams stainCongo redOil red OReticulin stain  <response>: Ans. b Congo redRef: Robbins pathology 9th ed. 1257 In biochemistry and histology, Congo red is used to stain microscopic preparations especially as a cytoplasm and erythrocyte stain. Apple-green birefringence of Congo red stained preparations under polarized light is indicative for the presence of amyloid fibrils. Additionally, Congo Red is used in microbiological epidemiology to rapidly identify the presence of virulent serotype 2A ShigellaFlexneri, where the dye binds the bacteriums unique lipopolysaccharide LPS structure 