Examinations
Examinations
Beta-2 microglobulin (B2M) is a protein found on the surface of many cells and is secreted into the body. Healthy individuals have small amounts of B2M in their blood and urine.
Clinical Significance
- Patients with bone marrow and blood cancers often have high levels of B2M in their blood or urine.
- These cancers include:
- Multiple myeloma
- Lymphoma
- Leukemia
- Elevated B2M levels in cerebrospinal fluid (CSF) may indicate cancer spread to the brain and/or spinal cord.
Limitations of B2M as a Tumor Marker
- The B2M test is not used for cancer diagnosis.
- However, it provides important prognostic information about cancer severity and potential progression.
- Sample: Blood drawn from a vein.
- Fasting for at least 8 hours before the test is required.
- Discontinue medications 24 hours before testing (if approved by the doctor).
- Autoimmune diseases (to assess disease activity).
- Cancer marker (for prognostic purposes in hematologic malignancies).
- Monitoring kidney transplant function.
Causes of Increased B2M Levels
Non-Cancerous Causes:
- Any inflammatory conditions
- Autoimmune diseases (e.g., systemic lupus erythematosus, Sjögren’s syndrome, rheumatoid arthritis)
- Viral infections (e.g., HIV/AIDS, cytomegalovirus infection, infectious mononucleosis)
- Kidney failure
- Hemodialysis (in some patients)
Cancer-Related Causes:
- Lymphoproliferative disorders, including:
- Multiple myeloma
- B-cell chronic lymphocytic leukemia (CLL)
- Non-Hodgkin’s lymphoma
- Hodgkin’s disease