E. Kretzschmar

Background and Objectives  Pooled nucleic acid amplification techniques (NAT) and donor screening for anti‐hepatitis C virus (HCV) have reduced the diagnostic window period of HCV infection in the blood donor population from about 12 to 1 or 2 weeks. During that time, HCV RNA is hardly detectable by pooled or individual donation NAT. Here we describe a case of transfusion‐acquired HCV infection from an extremely low‐titre donation. After a repeat donor tested positive for HCV, a look‐back procedure was initiated. A recipient of a red cell concentrate from the previous donation was identified and found to be infected with HCV as well. We compared several commercial NAT systems for their ability to detect the viraemic plasma.Materials and Methods  Molecular analyses of HCV in donor and recipient samples were performed. The HCV‐transmitting plasma was tested using different commercially available qualitative and quantitative NAT assays.Results  HCV transmission was verified by molecular analyses and was assigned to genotype 2b. NAT with various commercial HCV assays detected the infection erratically in individual donations. However, the detection rate was not directly related to the claimed sensitivity of some HCV NATs.Conclusions  HCV transmission can be caused by donations that escape NAT detection even when tested in an individual donation. Comparison of different assays led to results that did not necessarily reflect the expected sensitivities. The need for standard materials representing further HCV genotypes is discussed.

Background and Objectives  The aim of this study was to evaluate the quality of leucocyte‐depleted plasma produced from leucocyte‐depleted whole blood, stored for different periods of times before filtration through polyurethane filters.Materials and Methods  Whole blood was collected, from 48 voluntary donors, into quadruple blood bag sets with integrated whole‐blood filters, and stored at room temperature for 1, 2, 6, or 18 h before filtration. Five samples were taken: one directly from the donor; one immediately after collection; one before and one after filtration; and one from plasma units before freezing. All samples were analysed for the following parameters: prothrombin time; activated partial thromboplastin time; prothrombin fragments F1+2; fibrinogen; factors VIII, XI and XII; von Willebrand factor antigen; ristocetin cofactor activity; collagen‐binding capacity; multimers; and complement C3a‐desArg.Results  Different whole‐blood storage times before filtration did not have a significant effect on the stability of coagulation factors. The activity of all investigated coagulation factors in plasma was generally above 90 U/dl, even after 18 h of storage of whole blood before filtration. von Willebrand factor multimeric distribution remained stable throughout the process. However, activation of complement did occur during storage.Conclusions  Leucodepleted plasma originating from leucodepleted whole blood maintains a satisfactory level of coagulation factors, even after the storage of whole blood for 18 h at room temperature before filtration.