Beta-2 Microglobulin (Urine/Serum) Test Price in Dargha Bazar

Test Description

Beta-2 microglobulin (β2M) is a small (11.8 kDa) protein that forms the non-polymorphic component of all HLA class I molecules on all nucleated cells. It is shed into plasma at a rate dependent on cell turnover and HLA class I expression. Under normal conditions, β2M is freely filtered at the glomerulus, then almost completely reabsorbed and catabolized by proximal tubular cells (<1% excreted in urine). Normal serum β2M: 0.8–2.4 mg/L; normal urine β2M: <0.3 mg/L. Elevated serum β2M: reduced GFR (impaired renal clearance) — serum β2M rises progressively with CKD and correlates with GFR decline. It is used as a prognostic marker in multiple myeloma (ISS staging: stage I β2M <3.5 mg/L, stage II 3.5–5.5, stage III >5.5), CLL, and lymphoma. Elevated β2M also occurs with any condition causing increased cell turnover: autoimmune diseases, viral infections (HIV, CMV), inflammatory conditions. Elevated urine β2M with normal serum β2M indicates proximal tubular dysfunction (tubular proteinuria): cadmium nephropathy, Fanconi syndrome, Wilson disease, ifosfamide toxicity, aminoglycoside nephrotoxicity. It is used to monitor tubular function in HIV patients on tenofovir therapy.