Warm (IgG) – chronic anemia seen in SLE and CLL and with certain drugs (eg, α-methyldopa).

Cold (IgM and complement) – acute anemia triggered by cold; seen in CLL, Mycoplasma pneumonia infections, and infectious mononucleosis. RBC agglutinates may cause painful, blue fingers and toes with cold exposure.

Findings:- Autoimmune hemolytic anemias are usually Coombs ⊕- Direct Coombs test – anti-IgG antibody (Coombs reagent) added to patient's blood. RBCs agglutinate if RBCs are coated with Ig.- Indirect Coombs test – normal RBCs added to patient's serum. If serum has anti-RBC surface Ig, RBCs agglutinate when Coombs reagent added.