Alanine aminotransferase (ALT) levels were determined in 8,420 plasmapheresis donations obtained from 431 donors over a period of 18 months. Using sex-differentiated normal ranges 2.5% of donations but 23% of donors exhibited elevated ALT levels on at least 1 occasion. Amongst the donors with elevated ALT this was only seen on 1 occasion in one third, while a quarter had elevations in consecutive donations. No donors with consecutive elevations above 100IU/1 were detected. The results are discussed in terms of the guidelines currently recommended for assessing post-transfusion hepatitis infectivity of blood products, such as factor VIII. It is concluded that the current allowance for infection acquired from sources other than blood products under consideration may be over-generous, leading to a potential underestimate of the true rate of infection.

An approach to the full assessment of new plasmapheresis machines is outlined. This involves testing for changes in donated blood, donors and blood components using fresh donor blood and during full procedures in an animal model prior to performing full procedures in human volunteers. Using this approach, a new centrifugal plasmapheresis machine, the SPC-600, was assessed. No adverse effects associated with the use of the machine were detected in the initial studies. When used for plasmapheresis of volunteers, 500 ml of plasma was obtained in 43 ± 4 min without adverse effects on donors. The plasma product contained normal levels of plasma proteins, including factor VIII, and 20 ± 6 x 10^9/l platelets. There was no evidence of activation of complement or coagulation systems, and the factor VIII yield in cryoprecipitate prepared from single donations of plasma was equivalent to that observed for standard whole blood donations.