Blood type represent contributions from both parents. A total of 36 human blood group systems and 346 antigens are now recognized by the International Society of Blood Transfusion (ISBT). The two most important ones are ABO and the Rh blood group systems; they determine someone's blood type (A, B, AB and O, with +, − or null denoting RhD status) for suitability in blood transfusion. A complete blood type would describe a full set of 30 substances on the surface of red blood cells, and an individual's blood type is one of many possible combinations of blood-group antigens. Across the 36 blood
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