What type of autoimmune hemolytic anemia is indicated by positive polyspecific and IgG direct antiglobulin tests with no C3?

Warm autoimmune hemolytic anemia is characterized by the presence of antibodies that primarily react at body temperature, typically IgG antibodies. In this case, the positive results for both the polyspecific and IgG direct antiglobulin tests indicate that the patient’s immune system has produced antibodies against their own red blood cells, leading to hemolysis. The absence of C3 suggests that the destruction of red blood cells is primarily mediated by IgG antibodies rather than complement activation, which is common in conditions like cold agglutinin disease where C3 would typically be present.

Cold hemagglutinin disease would generally show positive reactions primarily with cold-reactive IgM antibodies, leading to a different pattern of complement activation. Transfusion reactions often result in both IgG and complement involvement depending on the timing and type of reaction, while drug-induced hemolytic anemias may also present with mixed results in direct antiglobulin tests, often showing a different profile.

Thus, the result pattern—positive for polyspecific and IgG with no C3—is highly indicative of warm autoimmune hemolytic anemia, where IgG plays the central role in the immune response against the red blood cells.