Monoclonal gammopathy of unknown significance (MGUS) is a blood condition in which a person's body makes too many of one type of white blood cell. These cells make a type of protein that fight infections.

MGUS doesn't usually cause symptoms or major health problems. It is often found by chance when lab tests are done for other reasons. Monoclonal antibodies can attach to nerves and cause numbness, tingling, and weakness. Most people with MGUS are fine for many years and do not need any treatment. In some cases, MGUS can change and progress to a cancer, such as multiple myeloma.

MGUS doesn't need treatment unless it turns into a serious condition. Your doctor will monitor your health to see if you need treatment.