Alternate Names: Bromosulphalein; BSP; 3,3'-(4,5,6,7-Tetrabromo-3-oxo-1(3H)-isobenzofuranylidene)bis [6-hydroxybenzenesulfonic acid] disodium salt; Disodium phenoltetrabromophthalein sulfonate; Phenoltetrabromophthalein-3',3?-disulfonic acid disodium salt