DAT positivity in blood donors: A perplexing scenario

A blood request was received for 70 year male patient suffering from Chronic Obstructive Pulmonary Disease with anemia. One unit was found incompatible in AHG phase. Patient's antibody screen, indirect antiglobulin test (IAT), direct antiglobulin test (DAT) and auto control was negative. DAT of donor unit was positive with anti IgG gel card and negative with C3d reagent along with positive auto control. Donor was 30 year male with no history of blood transfusion and medication and had no evidence of hemolysis. Donors with positive DAT should be deferred, notified and referred to physician but further studies are required.