Transfusion transmitted viral infections-recent developments in blood donor screening

Transmission of infectious diseases by the administration of blood, its components or derivatives, has been known since the beginning oftransfusion. However, 50 years ago, syphilis was the only disease which was serologically screened. Posttransfusion hepatitis (PTH) occurred in about 30% ofblood recipients in the US, but no laboratory test was available before 1969. During the last 20 years, the striking increase in the use of blood components and derivatives, and advances in the knowledge of diseases transmitted by blood has made this an area of major technological change, particularly where the screening of blood donors is concerned (Table I). In addition, the fear of developing the acquired immunodeficiency syndrome (AIDS) after transfusion has resulted in transfusion transmitted disease becoming a matter of major public concern, with significant effects on transfusion practice, and the acceptability to the individual patient of treatment with blood and blood products. The medico-legal consequences of blood transfusion have been highlighted by patients who have contracted human immunodeficiency virus (HIV) infection suing physicians, hospitals and transfusion centres and even demanding to know the identity of the blood donor who was the source of the infection. This brief article will concentrate on recent findings concerning the serological screening of blood donations in relation to transfusion transmitted viral infections in the last few years. The safety of blood and blood products with respect to transfusion transmitted infections depends primarily on the detection of the asymptomatic carrier with clinically unapparent disease. In addition, other factors may play an important role in the transmission of viral infections. Such factors include the amount of the infectious agent in the blood, the type and amount of blood or blood component transfused, the viability of the infecTable I Transfusion transmitted viral infections