Many plasmapheresis techniques cause greater activation of platelets, complement and coagulation than does simple whole blood collection. Activation of the coagulation cascade has been particularly evident in tests for potential thrombogenicity in prothrombin complex concentrates made from apheresed plasma. Attempts to improve the factor VIII content and fractionation yield of source plasma have centred on rapid freezing, increased concentration of anticoagulants and the exploitation of anticoagulants optimal for the preservation of coagulant, rather than cellular, activities. The cumulative advantage is of the order of 10% over recovered plasma. There are potential pitfalls in applying low-citrate anticoagulation strategies to plasmapheresis. Recalcification of citrated plasma, under cover of an optimal concentration of heparin, might be explored more vigorously. © 1995.