CD138 expression is a crucial marker in diagnosing plasma cell tumors and Multiple Myeloma cells. Traditionally, the evaluation of plasma cells from bone marrow involves a time-consuming and labor-intensive density gradient separation method using ficoll. However, this method leads to the loss of antigens, including CD138, from the plasma cell surface, necessitating immediate staining and analysis. This app note highlights the MARS® platform is a tool for efficient isolation of CD138+ plasma cells from unprocessed bone marrow samples. This innovative approach streamlines the isolation process, allowing for rapid and reliable analysis of CD138 expression in plasma cells.