Beta-2 microglobulin is a protein found on the surface of various cells in the body, including B lymphocytes and tumor cells. It is released into the blood and other body fluids. Elevated levels of this protein are associated with conditions that increase cell production, destruction, or stimulate an immune response. This test measures the presence of beta-2 microglobulin in the blood. Beta-2 microglobulin is present in high levels in the blood with cancers like multiple myeloma, lymphoma, and other inflammatory infections and disorders like
HIV and
CMV. Since the level of beta-2 microglobulin rises with blood cell cancers, it is useful as a tumor marker. ‘ Elevated levels of beta-2 microglobulin in cerebrospinal fluid may suggest brain involvement in individuals with blood cancer. Elevated levels are also associated with chronic disorders like multiple sclerosis and viral infections. On the other hand, in the kidneys, the test passes via the glomeruli, which are the blood filtering units, and is absorbed into the renal proximal tubules, which are structures that reabsorb water, proteins, minerals, and other substances. In general, small amounts of B2M are detectable in the urine, but when these structures get damaged, the B2M concentrations increase because the ability to reabsorb the protein goes down.