Beta 2 Microglobulin (B2M) Tumor Marker Test
The Beta 2 Microglobulin (B2M) tumor marker test is a laboratory procedure used to measure the level of B2M protein in the blood or urine. B2M is a small protein found on the surface of many cells, including lymphocytes, and is also present in small amounts in the blood and urine of healthy individuals.
What is Beta 2 Microglobulin?
Beta 2 Microglobulin (B2M) is a low-molecular-weight protein that is part of the major histocompatibility complex (MHC) class I molecule. It is produced by all nucleated cells and is found in small amounts in the blood, urine, and other bodily fluids.
What is the purpose of the B2M tumor marker test?
The B2M tumor marker test is used to help diagnose and monitor certain types of cancer, particularly multiple myeloma, lymphoma, and leukemia. Elevated levels of B2M in the blood or urine may indicate the presence of these cancers.
How is the test performed?
The B2M tumor marker test typically involves a blood draw or a urine sample collection. The sample is then sent to a laboratory for analysis, where the level of B2M is measured using techniques such as enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA).
Interpretation of results
The interpretation of B2M tumor marker test results depends on the individual's overall clinical picture and medical history. Elevated levels of B2M may indicate:
- Malignant diseases, such as multiple myeloma, lymphoma, or leukemia
- Chronic inflammatory conditions, such as rheumatoid arthritis or systemic lupus erythematosus
- Renal impairment or kidney disease
Normal levels of B2M do not necessarily rule out the presence of cancer or other diseases. Abnormal results should be interpreted in conjunction with other diagnostic tests and clinical findings.
Limitations and potential false positives
The B2M tumor marker test is not specific to cancer and can be elevated in various non-malignant conditions, such as:
- Chronic kidney disease or renal impairment
- Chronic inflammatory diseases
- Infections, such as HIV or hepatitis
False positives may occur due to laboratory errors, sample contamination, or other technical issues.
Clinical significance and applications
The B2M tumor marker test has several clinical applications:
- Diagnosis and monitoring of multiple myeloma, lymphoma, and leukemia
- Prognostic evaluation of patients with these cancers
- Monitoring response to treatment and detecting disease recurrence
Article last updated on: 15th June 2025.
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