How do Jehovah’s Witnesses view donating blood?
The Watchtower, May 15, 1950 p. 159 – Letter
It is freely acknowledged that the fluid from a person of one type of blood may kill a person of another type of blood. If, now, you donated your blood, and your type of blood killed the person receiving the transfusion, would you be guilty of murder? Or would the doctor or nurse that administered the transfusion be guilty of the murder? Would you not be at least an accessory to a murder?