Beta-2 Microglobulin (Serum or Plasma)
This test measures the level of beta-2 microglobulin, a small protein found in the blood that helps regulate immune responses and inflammation. It can be checked to assess kidney function, immune system health, or monitor certain conditions like multiple myeloma.
["Beta-2 microglobulin helps doctors evaluate kidney function and immune health."]
Key facts at a glance
- LOINC
- 32302-2
- Short code
- B2MU
- Synonyms
- B2 Microglob Ur-sCnc
- Category
- chemistry
- Sample
- urine
- Container
- Sterile, leak-proof urine collection container; preferably a plastic screw-cap container. For optimal stability, collection in a container with sodium bicarbonate or other alkaline buffer is recommended to maintain pH >6.
- Units
- N/A
- Ref low
- 0
- Ref high
- 0.03
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., Nephelometry, Chemiluminescent Immunoassay, or Turbidimetric Immunoassay)
- CPT
- 82232
- SNOMED
- 313507002
- Specimen volume
- 10 mL of random urine; 24-hour collection preferred for quantitative assessment (collect entire 24-hour volume and document total volume)
- Stability
- Unstable at acidic pH (<6); beta-2-microglobulin degrades rapidly in acidic urine. Stable for 1 day at 2-8°C if alkalinized; for longer storage, freeze at -20°C or below. Do not store at room temperature without pH adjustment.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order a beta-2 microglobulin test if you have symptoms or conditions that could affect kidney function, such as chronic kidney disease, immune disorders, or certain cancers like multiple myeloma. It may also be used to monitor treatment progress or check for complications in people with these conditions.
What to Expect Before the Test
No special preparation is usually needed for this test. You may have a small needle inserted into a vein (typically in your arm) to draw blood. If you’re having a urine test instead, you’ll need to collect a sample in a clean container. Always follow your healthcare provider’s instructions.
What the Test Results Mean
Beta-2 microglobulin levels can vary based on health status, age, and other factors. Higher than normal levels may suggest kidney problems, immune system issues, or certain cancers. Lower levels might indicate kidney disease or other conditions. Your results will be interpreted by a healthcare professional in the context of your overall health.
Common Conditions Monitored
This test is often used to monitor people with chronic kidney disease, multiple myeloma, or other conditions affecting the immune system. It can help track how well treatments are working or if kidney function is declining over time.
Reference range
Typically <0.03 mg/dL (<2.5 µmol/L) in random urine; or <0.2 mg/g creatinine (<0.03 mg/mmol creatinine) when normalized to urinary creatinine. Reference ranges vary by laboratory methodology and should be interpreted with the clinical context.N/A
No special preparation required. Patients should avoid strenuous exercise prior to collection as it may transiently affect results. Alkalinization of urine (pH >6) is recommended to prevent degradation of beta-2-microglobulin at acidic pH.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Beta-2 Microglobulin in Health and Disease
Short name
Beta-2 Microglobulin
Frequently asked questions
What are the normal reference ranges for beta-2 microglobulin?
Can beta-2 microglobulin levels change with diet or medications?
Is this test painful or uncomfortable?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy