The Preparation and Clinical Use of a New Concentrate Containing Factor IX, Prothrombin and Factor X and of a Separate Concentrate Containing Factor VII

S ummary A method of preparation for therapeutic use of a concentrate of factors IX, II and X and a separate concentrate of factor VII is described. The method is based upon adsorption of the factors on DEAE‐cellulose from plasma or from the supernatant after removal of factor VIII. Conditions of elution are selected so that, in a single step, the factors are obtained at a suitable salt concentration and potency to permit injection of a therapeutic dose by syringe. The yield of factor IX in vitro is about 50–75% and the purification about 300‐fold. The yield of factor VII is lower and variable. Experience in the use of 14 batches of factor‐IX concentrate in the treatment of 29 patients and on the use of a batch of factor‐VII concentrate in the treatment of one patient is described. The in vivo dose response to factor IX made by different methods is compared.