Direct Coombs test is positive for:
Autoimmune hemolytic anaemia in which the red cell injury is brought about by auto-antibodies reacting with antigens present on red cell membrane. 
Antiglobulin test (direct Coombs’ test) is employed to detect the antibody on red cell surface.

Key Point:
DAT (Direct Antiglobulin Test) testing typically involves the use of a polyspecific reagent consisting of IgG and complement C3.
Mohan H. Textbook of pathology. Jaypee Brothers Medical Publishers; 2015. Edition 7. Page 60
IgA
IgE
IgM
IgG