An immunoradiometric assay for factor III (tissue thromboplastin).

A solid-phase immunoradiometric assay for tissue thromboplastin (factor III) has been established based on its displacing effect on the binding of 125I-labelled factor III-antibodies to polyvinyl tubes coated with the purified protein component of factor III (apoprotein III). By this method circulating tissue thromboplastin can be detected in experimental animals receiving infusions of crude or purified tissue thromboplastin and in patients undergoing major orthopaedic surgery.