David Murray, MD, PhD, Mayo Clinic, Rochester, MN, outlines the use of mass spectrometry for the detection of monoclonal proteins (M-proteins) in multiple myeloma and related disorders. Electrophoretic detection has previously been used, however mass spectrometry has demonstrated superior sensitivity and is able to detect lower levels of disease. This method of detection has identified that patients with monoclonal immunoglobulin M-proteins with light chain glycosylation progress onto plasma cell disorders at a higher rate than those who do not. Prof. Murray also discusses how the use of monoclonal antibody therapies can cause interference with electrophoretic detection, and describes how mass spectrometry can overcome some of these interferences. Finally, Prof. Murray talks about the potential of developing a serum-based method for detection of measurable residual disease (MRD) using mass spectrometry. This interview took place during the 2021 European Myeloma Network (EMN) congress.