Adsorptions are used to dissociate (remove) autoantibodies from a patient's red blood cells in order to determine if an alloantibody(ies) is present.
There are two types of adsorptions: alloadsorption, performed if a patient has been transfused in the past three months, and autoadsorption if the patient has not been transfused in the past three months.
If the patient has not been transfused in the past three months, a full phenotype or genotype is performed (if not already known) to establish what alloantibodies the patient can form and to aid in antigen-negative transfusion of red blood cells (if recommended by your facility).
If the patient has been transfused in the past three months, and the phenotype or genotype is not known from previous blood bank encounters, the adsorption must rule out all alloantibodies. Genotyping is helpful at this point to know what antibodies the patient can form so that antigen-matched RBC units can be given to the patient for transfusion.
Any alloantibodies that cannot be ruled out by adsorption will likely require antigen-negative blood for that specific antigen as long as the antigen is clinically significant, and this practice is recommended by your facility.
