Congo Red


Chemical information

CI Direct Red 28; Colour Index No. 22120; Czerwień Kongo; Rojo Congo; Rubrum Congoensis. Disodium 3,3′-[biphenyl-4,4′diylbis(azo)]bis[4-aminonaphthalene-1-sulphonate].
Chemical formula: C32H22N6Na2O6S2 = 696.7.
CAS — 573-58-0.


Congo red is used as a stain in the diagnosis of amyloidosis. It causes amyloid in tissue samples to fluoresce under polarised light.
Published May 08, 2019.