Blood: Vital but Potentially Dangerous

This chapter describes the role of blood in the transmission of viruses and recounts early efforts to ensure the safety of the US blood supply. A person of average weight has approximately 5 quarts of blood containing more than 20 trillion individual cells. The discovery of blood groups by Karl Landsteiner in 1901 enabled the safe transfusion of blood, and transfusion therapy came into widespread use after World War II. However, it was soon recognized that donor blood could transmit infectious agents, and this was more likely to occur if the person giving the blood was motivated by a monetary reward. The frequency of transfusion-transmitted disease has been greatly reduced since 1985, when the Red Cross, other blood collectors, and the Food and Drug Administration began to rigorously screen donors and extensively test the donated blood. The chapter concludes by describing several recent advances that have further improved transfusion safety.