Coagulation factor content of cryoprecipitate prepared from methylene blueplus light virus-inactivated plasma

Levels of factor VIII (FVIII) and fibrinogen were assessed in control cryop recipitate and cryoprecipitate prepared in two centres from plasma subjecte d to methylene blue (MB) photochemical virus inactivation. The level of coa gulation FVIII activity was reduced in plasma by approximately 30% after MB photoinactivation, with only 44% (centre A) and 31% (centre B) of units me eting the current UK specification of 0.7 iu/ml. A revised specification of 0.5 iu/ml is suggested. Losses of less than 11% were seen for von Willebra nd factor (VWF)-related activities. Cryoprecipitate prepared from group O o r group A MB-treated plasma contained 27-40% less FVIII than control units, This reflected the lower levels in MB-treated plasma. The concentrating po wer of the cryoprecipitation process was not reduced for FVIII or fibrinoge n in MB-treated units, MB cryoprecipitate from centre A still met the UI( g uideline specification for FVIII and Fibrinogen content, whereas at centre B only 62.5% of the group 0 cryoprecipitates contained > 70 iu FVIII/unit. This may reflect the lower product volume and lower FVIII content of group 0 plasma used at centre B and suggests that maintenance of total coagulatio n Factor recovery in MB-treated cryoprecipitate will require the higher pro duct volume.