The test principle applied in this kit is Sandwich enzyme immunoassay. The microtiter plate provided in this kit has been pre-coated with an antibody specific to High Temperature Requirement Factor A4 (HTRA4). Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody specific to High Temperature Requirement Factor A4 (HTRA4). Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. After TMB subs