Transfusion recommendations can vary by facility. In general, it is recommended to transfuse Rh- and Kell-negative blood specific to the patient's phenotype as well as antigen negative to any alloantibodies the patient may have. This can be dependent on blood availability and the institution's policies. Because warm autoantibodies will likely interfere with a crossmatch, it may be recommended to transfuse the least incompatible, antigen-negative blood to the patient.
