Description
Overview: Beta-2 Microglobulin (B2M) is a small protein shed by cells into the blood, particularly by lymphocytes (immune cells). In healthy individuals, small amounts are present in the blood and urine. However, levels rise significantly when there is increased cell turnover (as in certain cancers) or when the kidneys are unable to filter it out properly.
Clinical Significance:
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Tumor Marker: Elevated B2M levels are a key prognostic factor in blood cell cancers such as Multiple Myeloma and Chronic Lymphocytic Leukemia (CLL). While it doesn’t diagnose the cancer itself, higher levels often indicate a larger tumor burden and a poorer prognosis, helping doctors stage the disease.
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Kidney Function: Since B2M is filtered by the kidneys, elevated serum levels can indicate kidney dysfunction or failure. (Note: A urine B2M test acts specifically to distinguish between different types of kidney damage).
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Inflammatory Conditions: Levels may also rise in chronic inflammatory diseases like lupus, rheumatoid arthritis, or viral infections (like HIV), reflecting an overactive immune system.
When is this test recommended?
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To evaluate the severity (staging) and prognosis of a newly diagnosed Multiple Myeloma or Lymphoma.
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To monitor the effectiveness of chemotherapy (falling levels suggest treatment is working).
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To distinguish between glomerular and tubular kidney disorders.
Sample Requirements:
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Specimen: Serum.
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Container: Gold Top (SST) or Red Top Tube.
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Preparation: No fasting is typically required.
