Test for blood Donation

Question 1

In DAT TEST, Why we have to identify igG or c3d ?

Answer 1

If the DAT is positive for immunoglobulin G (IgG) alone, or IgG and complement 3d, then the diagnosis is most probably WARM antibody.
Conversely, if the DAT is positive for complement 3d alone, then COLD antibody is most likely the diagnosis.