Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (835 page)

   Cold autoimmune hemolytic anemia/cold agglutinin disease.

   It is also positive when alloantibodies in a recipient’s circulation react with antigens on recently transfused red cells, as well as alloantibodies in maternal circulation, which cross the placenta and coat fetal red cells.

   Alloimmune (acute/delayed) hemolytic transfusion reactions.

   Hemolytic disease of the newborn.

   If the DAT is positive following recent transfusions, the antibodies can be eluted from RBCs and identified.

   Drug-induced reactions, such as

   Alpha-methyldopa

   
l
-Dopa

   High doses of penicillin

   Quinidine

   In patients who have not been transfused within the preceding 3 months, a positive DAT almost always reveals autoimmune antibodies.

Negative DAT

   Hemolytic anemias caused by an intrinsic RBC defect (e.g., G6PD [see p. 970], hemoglobinopathies [see p. 363])

   Limitations