Laboratory investigation of autoimmune hemolytic anemias.

The investigation of suspected autoimmune hemolytic anemias includes not only the laboratory investigation but also the patient's presenting symptoms and a complete medical history. A drug history is especially important if drug-induced hemolytic anemia is suspected. The patient's direct antiglobulin test results, both polyspecific and monospecific, guide the remainder of the workup. Serum and eluate testing may include untreated reagent red cells with and without the presence of unbound drug(s) and drug-treated reagent red cells. If autoantibodies are demonstrable in the serum, removal of those autoantibodies and subsequent testing for underlying alloantibodies is essential in the provision of safe blood for transfusion.