Congo-red with amyloid produces-
Blue colour
Dark brown colour
Brilliant pink colour
Khaki colour
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
General pathology