Packed red blood cells red cells with both are called AB. Except in unusual cases like infants or seriously immunocompromised individuals, all people will have antibodies to any ABO blood type that isn't present on their own red blood cells, and will have an immediate hemolytic reaction to a unit that is not compatible with their ABO type. In addition to the A and B antigens, there are rare variations which can further complicate transfusions, such as the Bombay phenotype. The Rh blood group system consists of nearly around 50 different antigens, but the one of the greatest clinical interest is the "D" antigen,
Jehovah's Witnesses and blood transfusions by failing to report any benefits of blood-based treatment. Nor do its publications acknowledge that in some situations, including rapid and massive haemorrhage, there are no alternatives to blood transfusions. He claims Watch Tower Society publications often discuss the risk of death as a result of refusing blood transfusions, but give little consideration to the prolonged suffering and disability, producing an added burden on family and society, that can result from refusal. Attorney and former Witness Kerry Louderback-Wood also claims that Witness publications exaggerate the medical risks of taking blood and the efficiency of non-blood medical therapies in critical situations.