Beta-2 Microglobulin

Beta-2-microglobulin (synonyms: β2-microglobulin, β2-Mi) is a protein (albumen; molecular weight, approximately 12,000) used as a tumor marker* , for renal diagnosis, and as a progression parameter in HIV infection. It is glomerularly filtered and 99.8% tubularly reabsorbed. If glomerular filtration is impaired, beta-2-microglobulin increases in serum; if tubular function is impaired, beta-2-microglobulin excretion in urine increases (= marker protein of tubular reabsorption function). It is thus also one of the marker proteins in urine. These allow differentiation and monitoring of nephropathies (kidney diseases). The HWZ of beta-2-microglobulin is 40 min. * Tumor markers are endogenous substances produced by tumors and detectable in the blood. They can provide an indication of malignant (malignant) neoplasm and are used as a follow-up test in cancer follow-up.

The procedure

Material needed

  • Blood serum
  • 24 h urine

Preparation of the patient

  • Not necessary

Disruptive factors

  • Not known

Normal value – blood serum

Standard value in mg/l
<3 months of age (LM) 2,8-3,4
3rd LM-1st year of life (LY). 1,8-2,2
Children 1,4-1,6
Adult 0,8-2,4
> 60TH LY < 3,0

Normal value – 24 h urine

Normal value in μg/l < 300

Indications

  • Suspected malignant (malignant) neoplasms: lymphoproliferative disorders (plasmocytoma (multiple myeloma), chronic lymphocytic leukemia (CLL), non-Hodgkin’s lymphoma (NHL), Burkitt’s tumor, Hodgkin’s lymphoma, adult acute lymphoblastic leukemia (ALL)).
  • Follow-up of malignant (malignant) neoplasms (see above).
  • Suspicion of nephropathies (kidney disease).
  • In nephropathies to assess the glomerular filtration rate (GFR; filtering capacity of the kidneys), especially in children.
  • Checking the functionality of kidney transplants.
  • Progression parameters in HIV infection

Interpretation

Interpretation of increased values

  • Malignancies (malignant neoplasms) such as:
    • Lymphoproliferative disorders (plasmocytoma (multiple myeloma), chronic lymphocytic leukemia (CLL), non-Hodgkin’s lymphoma (NHL), Burkitt’s tumor, Hodgkin’s lymphoma, adult acute lymphoblastic leukemia (ALL)) [in leukemias and lymphomas, beta-2 microglobulin is considered a prognostic parameter]
  • Nephropathies (kidney diseases) such as:
    • Renal function impairment (impaired GFR/glomerular filtration rate)/renal insufficiency (kidney weakness) [in renal insufficiency, beta-2 microglobulin is increased by a factor of 10-50].
    • Pyelonephritis (renal pelvic inflammation) – with increased values in the collected urine in pregnant women [values > 300 mg/l: V.a. infection of the upper urinary tract; values < 300 mg/l: pyelonephritis unlikely].
    • Tubular kidney damage [beta-2-microglobulin increase in the collection urine]
    • Decrease in GFR [beta-2-microglobulin rise in serum; assessment of renal function with beta-2-microglobulin is possible only when other (lymphoproliferative) diseases have been excluded]
  • Verification of renal transplant functionality [normalization of beta-2-microglobulin as a sign of functionality].
  • HIV infection – with the determination of ß2-microglobulin can be made a statement about the probable occurrence of AIDS in the case of elevated levels [beta-2-microglobulin levels in serum of > 5.0 mg/l → high risk of developing AIDS within 3 years]
  • Heavy metal intoxication/heavy metal poisoning, e.g., with cadmium (with elevated values in the collected urine).

Interpretation of lowered values

  • Not relevant to the disease

Further notes

  • Marker proteins in urine are:
    • Albumin – molecular weight (MG) 66,000; marker for glomerular proteinuria (increased excretion of protein in the urine due to damage to the glomerula (renal corpuscle)).
    • Transferrin – MG 90,000; marker for glomerular proteinuria.
    • Immunoglobulin G (IgG) – MG 150,000; marker for unselective glomerular proteinuria (indicative of severe glomerular damage).
    • Alpha-1-microglobulin – MG 33,000; marker of tubular proteinuria (restriction of tubular reabsorption function).
    • Alpha-2-macroglobulin.- MG 750,000; marker for postrenal proteinuria caused by bleeding (e.g., stones, infections, injuries, tumors).