Packed red blood cells do not have an antibody, since the greatest risk of Rh incompatible blood is to current or future pregnancies. For RBCs, type O negative blood is considered a "universal donor" as recipients with types A, B, or AB can almost always receive O negative blood safely. Type AB positive is considered a "universal recipient" because they can receive the other ABO/Rh types safely. These are not truly universal, as other red cell antigens can further complicate transfusions. There are many other human blood group systems and most of them are only rarely associated with transfusion problems. A screening test is
Jehovah's Witnesses and blood transfusions are now permitted by the WTS." He says the objection to blood transfusions on the basis of biblical proscriptions against eating blood is similar to the refusal of a heart transplant on the basis that a doctor warned a patient to abstain from eating meat because of his high cholesterol level. David Malyon, chairman of the English Hospital Liaison Committee in Luton, England, has claimed that Muramoto's discussion of the differences between consuming blood and alcohol is pedantic and says blood laws in the Bible are based upon the reverence for life and its association with blood, and that laws