WARNING! Transfusion complications
Despite improvements in crossmatching precautions, transfusion reactions can still occur. Unlike a transfusion reaction, an infectious disease transmitted during a transfusion may go undetected until days, weeks, or even months later when it produces signs and symptoms. Hepatitis C accounts for most posttransfusion hepatitis cases. The tests that detect hepatitis B and C can produce false-negative results and may allow some hepatitis cases to go undetected.
When testing for antibodies to human immunodeficiency virus (HIV), keep in mind that antibodies don't appear until 6 to 12 weeks after exposure. The estimated risk of acquiring HIV from blood products varies from 1 in 40,000 to 1 in 153,000.
What else can go wrong?
Circulatory overload and hemolytic, allergic, febrile, and pyogenic reactions can result from any transfusion. Coagulation disturbances, citrate intoxication, hyperkalemia, acid-base imbalance, ammonia intoxication, and hypothermia can result from massive transfusion.