Aminohydantion ( AHD) ELISA Test Kit 1. Principle This test kit is based on the competitive enzyme immunoassay for the detection of Aminohydantion ( AHD) in the sample. The coupling antigens are pre-coated on the micro-well stripes. The Aminohydantion ( AHD) in the sample and the coupling antigens pre-coated on the micro-well stripes compete for the anti-AHD 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 AHD in it. This value is compared to the standard curve and the AHD concentration is subsequently obtained.