Beta-2-Microglobulin (B-2-M), Urine
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Beta-2-microglobulin is a low-molecular-weight protein that forms the light chain component of class I histocompatibility (HLA: human leukocyte antigen) antigens.
Increased urine levels are seen in proximal tubular renal damage due to a variety of causes, including cadmium, mercury, lithium, or aminoglycoside toxicity; pyelonephritis; and Balkan nephropathy, a chronic interstitial nephritis of unknown etiology.
Evaluation of renal tubular damage
Monitoring exposure to cadmium and mercury
Increased excretion is consistent with renal tubular damage.
Beta-2-microglobulin excretion is increased 100 to 1,000 times normal levels in cadmium-exposed workers.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Degradation of beta-2-microglobulin occurs at pH <6.0. See Specimen Required for necessary collection requirements.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
< or =300 mcg/L
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. Ikeda M, Ezaki T, Tsukahara T, et al: Threshold levels of urinary cadmium in relation to increases in urinary beta2-microglobulin among general Japanese populations. Toxicol Lett 2003 Feb 3;137(3):135-141
2. Moriguchi J, Ezaki T, Tsukahara T, et al: Comparative evaluation of four urinary tubular dysfunction markers, with special references to the effects of aging and correction for creatinine concentration. Toxicol Lett 2003 Aug 28;143(3):279-290
3. Stefanovic V, Cukuranovic R, Mitic-Zlatkovic M, Hall PW: Increased urinary albumin excretion in children from families with Balkan nephropathy. Pediatr Nephrol 2002 Nov;17(11):913-916