Varying combinations of 3 measurable factors determine a patient's risk of progressing toward multiple myeloma and influence monitoring decisions. This review--and accompanying algorithm--can guide your approach. For monoclonal gammopathy of undetermined significance (MGUS) patients at low risk, repeat serum protein electrophoresis (SPE) in 6 months. If no significant elevation of M-protein is found, repeat SPE every 2 to 3 years.