MLT GlobeBeta-2 microglobulin (β2M)
Protein Electrophoresis · also called B2M, β2-microglobulin
What it measures
A small protein found on the surface of most cells and cleared by the kidneys. Blood levels reflect tumor burden in myeloma and lymphoma and help stage and predict outcome.
Specimen and preparation
- Specimen: Serum; urine for tubular injury studies
- Tube: Gold top
- Preparation: For urine testing keep pH above 6, since β2M degrades in acidic urine.
Reference range
| Group | Range |
|---|---|
| Adult (serum) | 0.8–2.2 mg/L |
| Adult (urine) | <0.3 mg/L |
Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.
Causes of high values
- Multiple myeloma (used in ISS staging)
- Lymphoma and CLL
- Kidney failure (reduced clearance)
- Renal tubular damage (urine β2M)
- HIV and viral infections, autoimmune disease
Method
Immunoturbidimetry, nephelometry or chemiluminescent immunoassay
Good to know
ISS stage III myeloma is serum β2M of 5.5 mg/L or more. Interpret with kidney function because low GFR raises levels independently.
Related tests
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