Strong cold autoantibodies can also make antibody screening difficult. Cold autoadsorption can be performed on patients not transfused in the past 3 months. In a cold autoadsorption, the patient's RBCs and patient plasma are incubated at 4ºC for 30–60 minutes. During this process, the autoantibodies are adsorbed to the patient's RBCs. Adsorbed sera can then be used to test against donor RBCs to identify clinically significant antibodies.
0.01 M DTT can also be used to perform antibody screening in the presence of cold autoantibodies. DTT can be added to the patient's plasma to inactivate the IgM cold agglutinin and allow antibody testing without the interference of the cold autoantibodies.
Important note: DTT destroys or alters Kell antigens. This will need to be considered in antibody workups.
