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 ANG-1 and Horseradish Peroxidase (HRP) conjugated ANG-1. The competitive inhibition reaction is launched between with HRP labeled ANG-1 and unlabeled ANG-1 with the antibody. A substrate solution is added to the wells and the c