Abstract: Objective To investigate the effect of Daratumumab (DARA) treatment on transfusion compatibility testing in patients with multiple myeloma, and to eliminate interference using a modified DTT method. Methods We collected samples from 11 patients with multiple myeloma treated with DARA in our hospital, and identified the effects of DARA treatment on irregular antibody screening testing and cross matching blood tests. After reagent red cells and donor red blood cells were treated with classical DTT method and modified DTT method respectively, irregular antibody screening and cross matching test were performed by microcolumn gel method. Then we evaluated the effectiveness of blood transfusion and observed adverse reactions of blood transfusion. Results After treatment with DARA, all patients exhibited positive reactions in both irregular antibody screening and the primary cross-matching by microcolumn gel method, while negative reactions by the polybrene method. When the modified DTT method (0.02 mol/L) was used to treat reagent red cells and donor red cells, the results showed negative reactions in both tests by the microcolumn gel method, which could accurately detect anti-K antibodies.The hemoglobin levels of patients increased, and there was no significant change in serum indirect bilirubin before and after transfusion, which indicating transfusion treatment was effective. No serious adverse reactions occurred. Conclusion DARA treatment could interfere transfusion compatibility tests. Modified DTT method would be an optional method for irregular antibody screening and cross matching.

Key words: Daratumumab, Multiple myeloma, Modified DTT method, Microcolumn gel method, Cross matching