Abstract: Objective To analyze the influence of anti-M antibody on blood transfusion compatibility test,the necessity of such antibodies for transfusion compatibility detection and clinical transfusion was found in advance, and then the importance of O cells in daily blood group identification was further explored. Methods The ABO typing discrepancy specimens were collected in the first blood group typing in the Department of Blood Transfusion of our hospital from January 2019 to December 2021, 18 of them were found to be anti-M positive by anti-human globulin test and other methods, and the influence of anti-M was eliminated by absorption-elution test and 2-mercaptoethanol. The red blood cells and serum after treatment were confirmed by forward and reverse typing, and cross-matching experiments were carried out by saline method, polybrene method and antiglobulin test. Results Among the 18 anti-M positive samples, 16 blood typing with discrepancy, antibodies were detected in reverse typing, 2 cases of type O specimens were not detected by automatic blood typing instrument, and O cells were found to be positive when the reverse type was rechecked by test tube method. After the anti typing of serum was rechecked by O cell absorption, the forward and reverse typing of all samples were consistent, and anti-M antibodies were detected in antibody identification. Cross matching test was carried out in 14 cases, of which 4 cases were infused with suspended red blood cells and other blood components, there was no adverse reaction of blood transfusion. The efficacy evaluation after blood transfusion found that the infusion was effective. Conclusion For the samples clearly caused by anti-M inconsistent match or cross blood incompatible, the interference caused by anti-M antibody can be eliminated and the correct experimental results can be obtained after the serum is treated with absorption test and 2-mercaptoethanol. However, the automatic blood group instrument alone is used to detect the blood group-deficient O cells with the cold-reactive saline antibodies to the anti-M class.

Key words: Anti-M antibody, ABO blood group determination discrepancy, Blood cross-matching test, Blood transfusion safety