The red-violet pigment formed by the condensation of diazotized sulfanilic acid with bilirubin in the van den Bergh reaction.
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azo·bil·i·ru·bin (a″zo-bilґĭ-roo″bin) bilirubin that has been diazotized by exposure to Ehrlich diazo reagent during the Jendrassik-Grof method of bilirubin measurement.Medical dictionary. 2011.