Experience of mandatory nucleic acid test (NAT) screening across all blood organizations in Germany: NAT yield versus breakthrough transmissions

Quality and Safety in Blood Supply in 2010

The past two decades saw tremendous achievements in blood safety, which are due to the commitment of blood establishments and industry, progress in technology such as the improvement of serological and NAT screening tests, and stringent regulatory control. Milestones in the legislation were the inclusion of plasma derivatives in the pharmaceutical legislation of the European Community (EC) in the year 1989 and special laws for the blood sector in EC and in member states, such as the Transfusionsgesetz (Transfusion Law) in Germany. The legal frame has to be supplemented by scientific and technical guidance, which is provided on the European level by the European Directorate for the Quality of Medicines and Health Care and by the European Medicines Agency. In the member states, guidelines taking into account the national peculiarities can be elaborated, such as the German hemotherapy guidelines issued by the German Medical Association (Bundesärztekammer) in agreement with the Paul-Ehrlich-Institut. The regulatory control of screening tests, and the introduction of NAT testing lead to a remarkably high degree of safety concerning the most relevant viruses HIV, HBV and HCV. Issues needing further attention are bacterial contamination and transfusion-associated acute lung injury (TRALI). Measures aiming at minimizing risks have to be balanced against their impact on supply. In order to ensure the assured supply with safe blood products, sustained efforts and research are needed as well as a continuous dialogue among blood services, industry, physicians, patients and regulatory authorities.

Quarantine Plasma: Quo vadis?

Upon the introduction of mandatory nucleic acid amplification technology (NAT) testing in Germany for HCV, quarantining of fresh frozen plasma (FFP) was reduced in 2002 from 6 to 4 months. In 2004 HIV-1 NAT and in 2005 anti-HBc testing were introduced to further reduce the residual transmission risks for transfusion relevant viruses. After testing more than 40 million donations by HCV NAT it became obvious that NAT testing has a very significant impact on viral blood safety by reducing the residual risk by a factor of 10. Only one documented HCV transmission occurred during more than 10 years of NAT testing in Germany, indicating that the remaining risk is marginal. Similar data were obtained for HIV-1. The question arises whether we could discontinue quarantining of FFP or further reduce the quarantining interval for retesting of the donor. This could facilitate logistics and reduce losses as quarantine FFP can be released earlier after donation and at regular donation intervals. Essential parameters for estimating the remaining infectious risks are the minimal infectious dose and replication kinetics of the viruses involved, the detection limits of the NAT tests applied, and the volume of plasma transfused. In essence it can be assumed that discontinuation of quarantining would only marginally increase the residual risk and that the reduction of the quarantine period to only 4 weeks would add an additional benefit to the viral safety of quarantine FFP.

The German Haemovigilance System--reports of serious adverse transfusion reactions between 1997 and 2007

Data of the German Haemovigilance System were collected from 1997 to 2007 and assessed on the basis of pre-defined safety standards. Suspected cases of serious adverse reactions following transfusions reported to the Paul-Ehrlich-Institut were evaluated on the basis of national criteria, and the definitions of International Society of Blood Transfusion (ISBT) in compliance with defined causality criteria. The suspected cases were rated as confirmed and unconfirmed transfusion reactions. Assessment of causality took into consideration the clinical course of the adverse reaction and, if necessary, information about donation and manufacturing. Of the 5128 suspected serious adverse reactions, 1603 could be confirmed. Referring to the absolute figures, acute transfusion reactions (e.g. allergic reactions, hypotension and dyspnoea) were recorded most frequently, followed by transfusion-related acute lung injury (TRALI), haemolytic reactions, transfusion-related bacterial infections and virus infections. The majority of the 52 transfusion-related fatalities (14 each) were due to TRALI and acute transfusion reactions (mostly severe allergic reactions). Referred to the blood products administered, immune TRALI cases and TRALI-related fatal courses were most frequently reported after administration of fresh frozen plasma (FFP) (15/10(6) and 3.5/10(6) units, respectively), transfusion-related bacterial infections after administration of platelet concentrates (7/10(6) units), acute haemolytic transfusion reactions after administration of red blood cell concentrates (2.3/10(6)units) and acute transfusion reactions after administration of red blood cell or platelet concentrates (7.8/10(6) and 13/10(6) units, respectively). Despite the high safety standard required for blood products in Germany, there is still room for reducing the frequency of isolated cases of transfusion reactions by targeted action.