With BCMA as the cornerstone marker and in combination with CD138, the assay is an ideal rare cell technology capable of simultaneously detecting and characterizing clonotypic B cells; plasmablasts; normal, malignant, and dendritic PCs; and other non-canonical BCMA-expressing cells, with potential impact in detecting myeloma cells in MGUS and SMM. This evidence concerns the gene SDC1 and plasma cell myeloma.