Cold autoantibodies can cause ABO discrepancies. These discrepancies can often be resolved by warming the patient's plasma and donor RBCs. In cases of strong cold autoantibodies, such as the ones seen in CAD, testing may need to be performed to inactivate the autoantibody.
For ABO and Rh typing, 0.01 M Dithiothreitol (DTT) can be used to inactivate the IgM cold agglutinin seen in cold autoantibodies. DTT treatment disrupts the disulfide bond of the IgM antibodies on the patient's RBCs preventing autoagglutination. This allows the blood bank to then perform ABO testing.
Important note: DTT destroys or alters Kell antigens. This will need to be considered in antibody workups.
