What is MGUS?
MGUS is defined as a paraprotein <3 g/dL, with <10% plasma cells in the bone marrow and no evidence of end-organ damage (no anemia, lytic bone lesions, hypercalcemia, or kidney disease attributable to the paraprotein).
Nearly 3% of individuals older than age 70 have MGUS. About 1% of patients with MGUS progress to symptomatic myeloma each year, so annual follow-up is required.
Patients with a higher level of paraprotein (>1.5 g/dL), non-IgG paraproteins, and an abnormal sFLC ratio at diagnosis are more likely to progress. Patients with MGUS usually have no or low levels of Bence-Jones proteins.
