Consider the blood tests used when evaluating a patient with autoimmune hemolysis. How does a DAT work? What is your differential diagnosis for a DAT + hemolytic anemia?
Direct Antiglobulin Test: Detects the presence of an antibody (IgG) or complement (C3d) bound in vivo to red blood cells in a patient’s circulation.
Coombs reagent is a monospecific immunoglobulin against IgG or C3 bound to the RBC surface. Agglutination indicates a positive test.
- Auto Antibody
- Warm autoimmune hemolytic anemia (positive test to IgG)
- Cold autoimmune hemolytic anemia (positive to C3d)
- Paroxysmal Cold Hemoglobinuria
- Drug effect
- Allo Antibody
- Transfused blood, IVIG
- Stem Cell transplant
- Hemolytic disease of the newborn
- MM/Plasma Cell dyscrasia