Packed red blood cells Rh type, specifically the phenotype, and the "screen" refers to testing for atypical antibodies that might cause transfusion problems. The typing and screening are also performed on donor blood. The blood groups represent antigens on the surface of the red blood cells which might react with antibodies in the recipient. The ABO blood group system has four basic phenotypes: O, A, B, and AB. In the former Soviet Union these were called I, II, III, and IV, respectively. There are two important antigens in the system: A and B. Red cells without A or B are called type O, and
Jehovah's Witnesses and blood transfusions Redstone to evaluate individual belief in respect to blood among Jehovah's Witnesses. The study showed that 12% were willing to accept transfusion therapy forbidden by Jehovah's Witness doctrine. One peer-reviewed study examining medical records indicated a similar percentage of Jehovah's Witnesses willing to accept blood transfusions for their children. Young adults also showed a willingness to accept blood transfusions. In another study, Jehovah's Witness patients presented for labor and delivery showed a willingness to accept some form of blood or blood products. Of these patients, 10 percent accepted whole blood transfusion. Watch Tower publications have noted that within religions, the