This assay employs the competitive inhibition enzyme immunoassay technique. The microtiter plate provided in this kit has been pre-coated with an antibody specific to DA. Standards or samples are added to the appropriate microtiter plate wells with Biotin-conjugated DA. A competitive inhibition reaction is launched between DA (Standards or samples) and Biotin-conjugated DA with the pre-coated antibody specific for DA. The more amount of DA in samples, the less antibody bound by Biotin-conjugated