Sudan red ELISA kit is a competitive enzyme immunoassay for the quantitative analysis of Sudan red in egg, feed and food.

The coupling antigens are coated on the micro-well stripes. The Sudan red in the  sample and the coupling antigens coated on the micro-well stripes compete for the anti-Sudan red antibodies. After the addition of the enzyme conjugate, the TMB substrate is added for coloration.

The optical density (OD) value of the sample has a negative correlation with the Sudan red in it. The measurement is made photometrically at 450nm. The absorption is inversely proportional to the Sudan red concentration in the sample.