MGUS: A Silent Blood Condition Worth Understanding

In the previous newsletters, I have talked about and discussed the testing and interpretation of these tests for monoclonal gammopathies. Over the next few posts, I will talk about each of the different plasma cell disorders in detail

We will start with Monoclonal Gammopathy of Unknown Significance or MGUS:

Monoclonal gammopathy of unknown significance (MGUS) is a common but often unnoticed blood condition where the body produces abnormal proteins called monoclonal proteins, or M proteins. These are made by plasma cells in the bone marrow.

MGUS typically causes no symptoms and is usually discovered incidentally during routine blood tests ordered for other reasons. It becomes more common with age, affecting roughly 3-5% of people over 50 and up to 7% of those over 70.

Diagnostic Criteria

MGUS is diagnosed when all three of the following criteria are met:

While MGUS itself is benign and doesn't require treatment, it matters because about 1% of people with MGUS per year develop multiple myeloma, a cancer of plasma cells, or related disorders like Waldenström macroglobulinemia or AL amyloidosis.

Because of this risk, people diagnosed with MGUS need regular monitoring through blood tests and physical exams, typically every 6-12 months. Doctors watch for warning signs like increasing M protein levels, anemia, kidney problems, or bone pain.

The good news? Most people with MGUS never develop complications and live normal, healthy lives.

To learn more about the testing for plasma cell disorders, click here to understand the SPEP and here if you want to learn more about the light chains!

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