What is the M band, and what does it indicate in multiple myeloma?

The M band, or monoclonal band, is a key marker in diagnosing multiple myeloma, a cancer of plasma cells in the blood. This band appears on a test called serum protein electrophoresis, which helps doctors see different proteins in the blood.

What is the M Band?

• Monoclonal Band: The M band shows up as a distinct band on the serum protein electrophoresis test. It represents an abnormal amount of a single type of protein, usually produced by cancerous plasma cells.

What Does It Indicate?

• Multiple Myeloma: The presence of an M band can suggest multiple myeloma, where these abnormal plasma cells grow uncontrollably and produce a large amount of a single antibody.
• Double M Bands: In some cases, more than one M band can appear, indicating a more complex situation, which might require further investigation.

This test is essential because it helps doctors understand how much of this abnormal protein is in the blood, which can aid in diagnosing and monitoring the disease.