Multiple Myeloma is a malignant disease of the bone marrow plasma cells that mainly affects older people, and whose prognosis is reserved on relapsing or refractory disease. The arrival of CD38 monoclonal antibody daratumumab into the market allowed an increase in overall survival rate, with limited associated toxicity, for pre-treated multiple myeloma patients. However, this antibody interferes with pre-transfusion tests since erythrocytes also express, even at reduced levels, CD38 receptors. A literature review and discussion about this topic was performed by a board of Portuguese Immuno-hemotherapy experts. Based on the literature review, the mechanisms by which daratumumab interferes with pre-transfusion tests and may mask the presence of irregular antibodies in plasma of treated patients, which may result in difficulties in preparing and delivering results and blood components to be transfused, were identified and discussed. In addition, the applicable strategies in clinical practice to mitigate this interference were identified, namely the denaturing method of CD38 with dithiothreitol, considered an inexpensive, reproducible, reliable and validated technique, although with logistic limitations and should not be ignored. The experts also assessed and discussed the main concerns and priorities of transfusion medicine services, considering the limitations of this technique and its implication in routines for tranfusional support. The experts agreed on the importance of communication between physicians, hematologists, immuno-hemotherapy specialists, nurses and patients, as well as the need to align all methodologies to develop global and universal protocols to the various clinical analysis laboratory centers.

Keywords: Blood tests, Daratumumab, Dithiothreitol, Transfusion Medicine