The Food and Drug Administration has cleared Sebia’s Hydrashift 2/4 daratumumab assay, an immunofixation electrophoresis-based test for monitoring treatment response in multiple myeloma patients. This test mitigates the interference seen in immunofixation results for multiple myeloma patients treated with Darzalex (daratumumab), a fully human monoclonal antibody that binds to the CD38 glycoprotein found on the surface of immune cells. Developed in collaboration with Janssen Biotech, the Hydrashift 2/4 daratumumab assay is designed for use with the Hydragel IF kit and the semiautomated Hydrasys 2 electrophoresis instrument. The test works by creating a daratumumab/anti-daratumumab immune complex to shift daratumumab in the alpha-1-zone. This complex is then visible in the IgG and kappa immunofixation tracks. A negative Hydrashift 2/4 daratumumab result demonstrates the absence of endogenous M-protein and indicates a patient’s complete response. This test is not intended for use, however, with patient samples with other interfering monoclonal antibodies.