Beta-2 Microglobulin, Serum
Evaluate the severity and prognosis of multiple myeloma, chronic lymphocytic leukemia, or non-Hodgkin’s lymphoma; detect kidney damage and distinguish between glomerular and tubular kidney disorders.
Drugs such as lithium, cyclosporine, cisplatin, carboplatin, and aminoglycoside antibiotics can increase β2-microglobulin concentrations. β-2microglobulin (β2MG) is a small membrane protein that is a component of the class I major histocompatibility complex found on the surface of all nucleated cells. β2MG is especially abundant on the surface of white blood cells so increased production or destruction of these cells causes serum levels to increase. Levels of β2MG can be increased in patients with chronic inflammation, some viral infections, and in several hematologic malignancies associated with the β-lymphocyte lineage.
Serum β2MG is often measured to assess the severity of multiple myeloma and Waldenström’s macroglobulinemia and to monitor the effectiveness of treatment. Significantly elevated levels are associated with a poorer prognosis. Greipp and associates devised a simple calculation (the International Staging System) using serum β2MG and albumin for the classification and stratification of patients with multiple myeloma. The utility of this calculation has been reviewed along with the potential for enhancement by addition of other biomarkers. Measurement of serum β2MG is also helpful in patients with leukemia or lymphoma to help determine stage of disease and independent predict progression-free survival. β2MG levels also rise during infection with some viruses, including cytomegalovirus and human immunodeficiency virus.
In the healthy kidney, β2MG passes through the glomeruli, and is then almost completely reabsorbed by the proximal tubules. In someone with signs of kidney disease, measurement of serum and urine β2MG can be useful in distinguishing between glomerular and tubular disfunction. Serum β2MG levels increase with the progression of chronic kidney disease. In patients on long-term hemodialysis, β2MG can aggregate into amyloid fibers that deposit in joints and tissues, causing stiffness and pain in a condition referred to as dialysis-related amyloidosis. Serum β2MG levels are a significant predictor of mortality in haemodialysis patients.
Recently, serum β2MG has been shown to be an independent predictor of mortality in older adults. This study found that increased baseline serum β2MG was an independent predictor of increased cardiovascular events and cardiac mortality.
Red-top tube or gel-barrier tube
If a red-top tube is used, transfer separated serum to a plastic transport tube.