Daratumumab interference in flow cytometric anti-granulocyte antibody testing can be overcome using non-human blocking antibodies.

Background: Daratumumab (DARA), a human IgG1 monoclonal antibody targeting CD38, is used to treat refractory multiple myeloma patients. CD38 is expressed on many cell types (RBCs, granulocytes, lymphocytes, etc.), and thus, DARA can interfere with serological tests.