This assay employs the competitive inhibition enzyme immunoassay technique. The microtiter plate provided in this kit has been pre-coated with goat-anti-rabbit antibody. Standards or samples are added to the appropriate microtiter plate wells with an antibody specific for IFN-beta and Horseradish Peroxidase (HRP) conjugated IFN-beta. The competitive inhibition reaction is launched between with HRP labeled IFN-beta and unlabeled IFN-beta with the antibody. A substrate solution is added to the wel