Interpretive Data:

Beta-2 M is measured by an immunoturbidimetric assay (Optilite, The Binding Site). Results by other assays should not be used interchangeably due to differences in analytical methods. Beta-2 M is a low molecular weight protein (11.8kD) found on the surface of most nucleated cells. It forms the light chain component of the histocompatibility antigen and is eliminated via the kidneys. Following filtration through the glomeruli it is reabsorbed an d catabolized by the proximal tubular cells. Normally only trace amounts are excreted in the urine. However this is markedly increased in tubulointerstitial disorders. Raised serum levels of Beta-2 M are associated with renal disease and rheumatoid arthritis. E levated serum levels can also occur with systemic lupus erythematosus, malignant lymphoma and myeloma.