Beta-2 microglobulin is a protein that is found on the surface of the majority of cells in the human body and is shed by the cells into the blood.
Beta2-microglobulin is abundant on the surface of white blood cells. Increased production or destruction of these cells causes Beta2-microglobulin levels in the blood to increase. This increase is seen in people with cancers involving white blood cells, but it is particularly meaningful in people newly diagnosed with multiple myeloma. Multiple myeloma is a cancer of a certain kind of white blood cell, called a plasma cell. At the time of diagnosis, the Beta2-microglobulin levels reflect how advanced the disease is and the likely prognosis for that person.

Because Beta-2 Microglobulin is increased with blood cell cancers, it may be useful as a tumor marker. Though it can be used to assess kidney function as well.
HIGH VALUES:
- Elevated concentration levels of beta-2 microglobulin is attributed to diseases with a high cell turnover. It is a powerful prognosis factor for multiple myeloma, a type of bone marrow cancer. It is also used to detect chronic lymphocytic leukemia and some types of lymphomas.
- In glomerular kidney disease, the glomeruli can’t filter it out of the blood, so levels increase in the blood and decrease in the urine.
- After a kidney transplant, increased blood levels may be an early sign of rejection, toxic amounts of anti-rejection medication, or a viral infection.
- An increased level in a worker exposed to cadmium or mercury may signal beginning kidney damage.
- Possible virus infection (ex: cytomegalovirus or HIV).
LOW VALUES:
- Low levels of Beta2-microglobulin (as a tumor marker) are considered normal and good.
- When kidney disease is suspected, comparing blood and urine levels helps identify where the kidney is damaged.
References:
- Bataille R, Magub M, Grenier J, et al: Serum beta-2-microglobulin in multiple myeloma: Relation to presenting features and clinical status. Eur J Cancer C
- Karlsson FA, Wibell L, Evrin PE: Beta-2-microglobulin in clinical medicine. Scand J Clin Lab Invest 1986;154:27-37
- https://www.cancer.org/cancer/multiple-myeloma/about/what-is-multiple-myeloma.html
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