Resolving crossmatch incompatibility due to daratumumab in multiple myeloma

Daratumumab (DARA) is an anti-CD38 monoclonal antibody which has promising results in relapsed and refractory multiple myeloma. DARA interferes with blood compatibility testing by causing panagglutination in the indirect antiglobulin test. In all incompatibilities, immunohematology workup must be done to rule out allo- or autoantibody and to issue compatible unit to the patient. Transfusion support is vital for all these patients with incompatibility and should not be delayed. We encountered one such patient who was undergoing treatment with DARA for refractory multiple myeloma and had incompatibility during crossmatching. Many methods are available to sort out this problem. These include anti-CD38 idiotypes, cord blood, trypsin, papain, dithiothreitol (DTT) treatment, phenotyping, and genotyping. We hereby report resolving the above discrepancy by one of the simplest, cheapest, and feasible methods, i.e., DTT treatment in our blood centers.