Many of the recent advances in modern blood transfusion are due to the development of an anti-globulin test or coombs test. Without this invention, the pathology of most hemolytic anemia remains undoubtedly unclear. We also witnessed at least the delayed hemolytic transfusion reactions. Despite the use of hemagglutination-enhancing agents such as polyethylene glycol, low ionic strength saline, albumin and various enzymes, some IgG antibodies are not able to produce hemagglutination. The anti-globulin reagent allows the detection of hemagglutination by creating a bridge between the pre-sensitized red blood cells with antibodies or complements. In this document, the implementation requirements of the coombs test and the quality control and validation of its results was discussed.