A coagulation reagent completely devoid of factor X; Relation between clotting time and concentration of factor X

Abstract

A reaction mixture completely devoid of factor X is described. It is shown that no pathways of blood coagulation exist that circumvent this factor. The relation between the clotting time and the inverse of the factor X concentration is shown to be rectilinear. The low K M of the rate-limiting reaction explains why trace amounts of factor X cause short clotting times.