Test Catalog

Test ID: B2MC    
Beta-2-Microglobulin (Beta-2-M), Spinal Fluid

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluation of central nervous system inflammation and B-cell proliferative diseases

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Beta-2-microglobulin (BETA-2-M) is a small membrane protein (11,800 Dalton) associated with the heavy chains of class I major histocompatibility complex proteins and is, therefore, on the surface of all nucleated cells. The small size allows BETA-2-M to pass through the glomerular membrane, but it is almost completely reabsorbed in the proximal tubules.


Increased BETA-2-M levels in the cerebrospinal fluid (CSF) have been shown to be of diagnostic use in non-Hodgkin lymphoma with central nervous system involvement. Elevated CSF:serum ratios seen in patients with aseptic meningo-encephalitis suggest the possibility of neurologic processes including those associated with HIV infection and acute lymphoblastic leukemia. BETA-2-M measurement in multiple sclerosis seems to be of indeterminate usefulness.

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.

0.70-1.80 mcg/mL

Interpretation Provides information to assist in interpretation of the test results

Elevations of cerebrospinal fluid beta-2-microgobulin levels may be seen in a number of diseases including malignancies, autoimmune disease, and neurological disorders.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Koch T, Lichtenfeld K, Wiernik P: Detection of central nervous system metastasis with cerebrospinal fluid beta 2 microglobulin. Cancer 1983;52:101-104

2. Mavligit G, Stuckey S, Fernando B, et al: Diagnosis of leukemia or lymphoma in the central nervous system by beta 2 microglobulin determination. N Engl J Med 1980;303:718-722

3. Jeffrey G, Frampton C, Legge H, et al: Cerebrospinal fluid beta 2 microglobulin levels in meningeal involvement by malignancy. Pathology 1990;22:20-23

4. Us O, Lolli F, Baig S, Link H: Intrathecal synthesis of beta 2 microglobulin in multiple sclerosis and aseptic meningo-encephalitis. Acta Neurol Scand 1989;80(6):598-602

5. Elovaara I, Livanainen M, Poitainen E, et al: CSF and serum beta 2 microglobulin in HIV infection related to neurological dysfunction. Acta Neurol Scand 1989;79(2):81-87

6. Dolan MF, Lucey DR, Hendrix CW, et al: Early markers of HIV infection and subclinical disease progression. Vaccine 1993;11(5):548-551

7. Brew BJ, Bhalla RB, Fleisher M, et al: Cerebrospinal fluid beta 2 microglobulin in patients infected with human immunodeficiency virus. Neurology 1989;39(6):830-834

8. Musto P, Tomasi P, Cascavilla N, et al: Significance and limits of cerebrospinal fluid beta 2 microglobulin measurement in course of acute lymphoblastic leukemia. Am J Hematol 1988;28(4):213-218

9. Lucey DR, McGuire SA, Clerici M, et al: Comparison of spinal fluid beta 2-microglobulin levels with CD4 + T cell count, in vitro T helper cell function, and spinal fluid IgG parameters in 163 neurologically normal adults infected with the human immunodeficiency virus type l. J Infect Dis 1991;163:971

10. Bjerrum L, Bach F, Zeeberg I: Increased level of cerebrospinal fluid beta 2 microglobulin is related to neurologic impairment in multiple sclerosis. Acta Neurol Scand 1988;78:72-75