What is monoclonal gammopathy of undetermined significance (mgus)?

Lab finding, pre-MM: Mgus is monoclonal gammopathy of undetermined significance. It was called "benign monoclonal gammopathy" until ~1975 when robert kyle published an article in the nejm. Myeloma is thought to evolve from mgus at about 1% per year. Mgus risk factors can increase or decrease that risk.

Blood & urine tests: Mgus is the presence of an abnormal protrein in the blood made by a type of white blood cell called a plasmacyte. In most cases, it is at a low level and is something that just has to be followed. However, it can be the precursor of the disease called multiple myeloma and as such a hematologist or medical oncologist will order tests to rule this out which may include blood, urine and simple x-rays.