What is monoclonal gammopathy of unknown significance?

Most people with MGUS don't need any treatment. But you may need regular physical exams, blood tests, and urine tests to make sure that MGUS isn't progressing to a medical problem.

MGUS is often found by chance when blood tests are done for other reasons. If you have high levels of a certain protein in your blood, your doctor may order more tests. Blood tests can help identify the protein. The protein is sometimes found in the urine, so you may get a urine test too.

Other tests may be done if your doctor thinks you might have a medical problem. In some cases, a bone marrow biopsy may be done to rule out a problem like multiple myeloma.

Monoclonal gammopathy of unknown significance (MGUS) is a blood condition. The blood is made of many kinds of cells, including red blood cells, platelets, and white blood cells. With MGUS, a type of white blood cell called a plasma cell makes too much of the "M" (for "monoclonal") protein in the blood.

Most people with MGUS are fine for many years. MGUS seldom causes symptoms or major health problems. In rare cases, MGUS may turn into multiple myeloma. This is a cancer of plasma cells in the blood that can cause bone weakness. Some people with MGUS may also have a higher risk for osteoporosis, in which bones become thin and weak.

MGUS is sometimes seen in younger people, but is more common in people as they get older. It's seen most often in those over the age of 70.