Principle of the Assay The AssayMax Human Tissue Factor (TF) ELISA kit is designed for detection of human TF in plasma, serum, tissue extracts, and cell culture samples. This assay employs a quantitative sandwich enzyme immunoassay technique that measures TF in less than 5 hours. A polyclonal antibody specific for TF has been pre-coated onto a 96-well microplate. TF in standards and samples is sandwiched by the immobilized antibody and the biotinylated polyclonal antibody specific for TF, which is recognized by a streptavidin-peroxidase conjugate. All unbound material is then washed away and a peroxidase enzyme substrate is added. The color development is stopped and the intensity of the color is measured.