Blood Transfusion and Transmissible Disease

During the past 30 years great advances have been made in preventing what were the commonest forms of adverse transfusion reactions: namely pyrogenic reactions, circulatory overloading, haemolytic reactions and bacterial con­ tamination of donations. This has been achieved by the combined efforts of transfusion centres, hospital laboratories and clinical u sed of donor blood to promote safer transfusion practices. In particular, care in collecting a n d storing blood, the performance of sensitive grouping and matching tests a n d attention t o the volume and rate of transfusion have helped to reduce the incidence of adverse reactions. One result of this achievement has been t o focus attention on the need to prevent the transmission of infective agents by transfusion. Maycock (1972) stated that the transmission of viral hepatitis was the most serious complication of the use of blood and blood products. That emphatic statement was made a t a time of great concern arising from the many serious outbreaks of viral hepatitis in chronic renal dialysis and transplant surgery units. Measures for the prevention of hepatitis in patients with chronic renal failure were discussed in detail (Department of Health and Social Security, 1972a) and practical recommendations were made t o avoid the transmission of hepatitis by transfusion (Department of Health and Social Security, 1972b). The most important preventive measure against the transmission of communicable diseases is the avoidance of unnecessary transfusions. A single donation may be used to provide as many as six different blood components. Thus a n infective agent in one donation may be disseminated into multiple blood products. Similarly, because blood products are prepared from a large number of pooled donations, a recipient may be exposed t o infective agents f rom multiple blood donors. Recipients may not have normal immune competence because of the primary disease o r immunosuppressive therapy. The severity and consequences of adverse transfusion reactions depend in part on the clinical condition and immune state of the host. Consideration of the transmission of communicable diseases must be seen against this background of preventive measures, sophisticated blood com­ ponent therapy and the state of the patient. In transfusion therapy it is