This assay employs the competitive inhibition enzyme immunoassay technique. A monoclonal antibody specific to PGD2 has been pre-coated onto a microplate. A competitive inhibition reaction is launched between biotin labeled PGD2 analogues and unlabeled antigen (Standards or samples) with the pre-coated antibody. After incubation the unbound conjugate is washed off. Next, avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. The amount of bound HRP conju