Beta 2-microglobulin: its significance and clinical usefulness.

beta 2-Microglobulin (beta 2M), an interesting and underutilized metabolite, can be used in assessing renal function, particularly in kidney-transplant recipients and in patients suspected of having renal tubulointerstitial disease. It also can serve as a nonspecific but relatively sensitive marker of various neoplastic, inflammatory, and infectious conditions. Early hopes that it would be a useful serum test for malignancy have not been fulfilled, but it does have prognostic value for patients with lymphoproliferative disease, particularly multiple myeloma. More recent reports have suggested a role for beta 2M as a prognostic marker in human immunodeficiency virus (HIV) infection.