Monoclonal gammopathy of undetermined significance: A primary care guide

Monoclonal gammopathy of undetermined significance (MGUS) is commonly diagnosed in outpatients being worked up for an array of clinical concerns. It carries a risk of progression to myeloma and other lymphoproliferative disorders that, albeit low (1% per year), warrants regular follow-up. Patients with MGUS can be risk-stratified on the basis of the amount and type of their monoclonal protein as well as whether they have an abnormal light-chain ratio. Here, we provide a guide to the diagnosis, workup, and management of MGUS.