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Test Name:
Beta-2-Microglobulin, Urine
- SBMF No:
30007 - Performance Lab Name:
Manual Lab - Test Mnemonic:
U B2-M - ABN:
May be required – Medical Necessity - CPT Code:
82232 - LOINC Code:
1953-9 - Also Known As:
B2M - Also See:
30008 – Beta-2-Microglobulin, Serum
30006 – Beta-2-Microglobulin, Cerebrospinal Fluid - Spec Type:
Urine - Spec Container:
Plastic container with tightly fitting lid - Pref Vol:
1.0 mL - Min Vol:
0.3 mL - Fasting:
No - Spec Collect:
Have patient void (completely empty bladder)
Next, have patient drink a large glass of water and collect a urine sample within 1 hour
Once collected, adjust the pH of the urine to between 6 and 8 with 1.0 M NaOH - Spec Process:
Refrigerate or freeze pH-adjusted urine specimen - Spec Store Transport:
Refrigerated (48 hours) or frozen - Spec Stability:
48 hours refrigerated (2-8°C)
2 weeks frozen (-20°C) – Do not use frost-free units that undergo repeated freeze/thaw cycles - Methodology:
Chemiluminescent Immunoassay (CLIA) - Use:
Evaluate renal disease, activity of chronic lymphocytic leukemia, or AIDS activity - Clinical Significance:
Beta-2 Microglobulin (B2M) comprises the light chain of the major histocompatibility antigen and is found on the surface of most nucleated cells. It is found in both serum and urine of normal individuals. B2M readily passes through the glomerular membrane and is reabsorbed and degraded in the proximal tube. Proximal tubular dysfunction results in elevated concentrations of urinary B2M, thereby providing a means of distinguishing proximal tubular from glomerular renal diseases.Serum levels of B2M are a function of its rate of synthesis or release into the serum pool and its rate of clearance. In inflammatory disorders (e.g., rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s Syndrome and Crohn’s disease) and in lymphoproliferative diseases (e.g., multiple myeloma, b cell lymphoma and chronic lymphocytic leukemia), serum B2M levels are frequently elevated reflecting an increased rate of synthesis. Serum levels are also elevated because of decreased rates of clearance of this protein due to renal insufficiency as described above. - Reference Range:
Less than or equal to 300 µg/L - Day Run:
Mon, Wed, Fri - Time Run:
8:00 am - Time Reported:
5:00 pm - Test Type:
URINE
