Abstract
Mass spectrometry provides a highly sensitive and specific way to detect low level monoclonal proteins in multiple myeloma. Two main approaches – the intact light chain approach and the clonotypic peptide approach – have been developed and several assays are now commercially available, with some moving into clinical use for routine M-protein testing. Multiple studies have compared the performance of mass spectrometry to established bone marrow–based minimal residual disease (MRD) tests and have provided early insights into its clinical utility in the setting of MRD. This review summarizes the different mass spectrometry methods for M-protein detection, discusses our current understanding of their clinical utility for MRD testing, and describes what the next steps might look like for these promising techniques.