Congo-red with amyloid produces-: (A) Blue colour, (B) Dark brown colour, (C) Brilliant pink colour, (D) Khaki colour
Answer is C. The histologic diagnosis of amyloid is based almost entirely on its staining characteristics. The most commonly used staining technique uses the dye Congo red, which under ordinary light impas a pink or red color to amyloid deposits. Under polarized light the Congo red-stained amyloid shows so- called apple-green birefringence Robbins 9 th edition page no. 156