A Two-Stage Assay Method for Hageman Factor Activity

Abstract

A two-stage assay method for assaying Hageman factor (HF) activity has been described. The method is based on the ability of a diluted test plasma or surface factor preparation to correct the clotting defect of a HF-deficient substrate plasma in a modified thromboplastin screening test. This method, being designed for investigating relative increase or decrease of HF activity, could also be used in a system with optimal amount of kaolin for assaying maximal HF activity. ^* Aided by a USPHS Grant No. H-1510.