This kit was based on sandwich enzyme-linked immune-sorbent assay technology. Thyroid peroxidase was pre-coated onto 96-well plates. And the Biotin- labeled Thyroid peroxidase was used as detection antigen. The standards, test samples and Biotin- labeled Thyroid peroxidasewere added to the wells subsequently, and wash with wash buffer. HRP-Streptavidin Conjugatewas added and unbound conjugates were washed away with wash buffer. TMB substrates wereused to visualize HRP enzymatic reaction. TMB