The test is rarely requested when investigating kidney disease due to poor specificity. However it may be requested when you have symptoms and signs associated with kidney dysfunction; due to possible cadmium kidney toxicity. However the main use of B2M in the UK is in multiple myeloma (see the Beta-2 Microglobulin Tumour Marker article) not in kidney disease.
Beta-2 microglobulin (B2M) is not a frequently requested test in the UK, however it may be used to detect and localise kidney damage and follow kidney disorders.
A blood sample drawn from a vein in your arm and/or a random or 24-hour urine sample.
None
Beta-2 microglobulin (B2M) is a protein that is found on the surface of cells and functions as part of the human immune system (component of MHC class I). This protein is routinely shed by cells into the blood and is present in most body fluids, with the highest levels found in blood and very low (trace) levels found in urine.
In the kidneys, B2M passes through blood-filtering units called the glomeruli and is then reabsorbed by the renal proximal tubules, structures that reclaim water, proteins, vitamins, minerals, and other vital substances. Normally, only small amounts of B2M are present in the urine. If the renal tubules become damaged or diseased, B2M concentrations increase in the urine due to the inability of the tubules to reabsorb this protein. If the glomeruli in the kidneys are damaged, then they are unable to filter out B2M, so the level in the blood rises