S-Beta-2-microglobulin is a protein that is part of the MHC class I complex and is released during normal cell turnover. The protein is filtered by the kidneys and circulates in the blood at relatively low concentrations in healthy individuals. Elevated levels of B2M can result from increased production in diseases where the immune system is active, particularly in lymphoproliferative disorders such as multiple myeloma, lymphoma, and leukemias. Since B2M is also excreted through the kidneys, its levels may rise in cases of impaired kidney function.
In healthcare, B2M is sometimes used as a tumor marker to assess disease activity and prognosis in blood cancers. In multiple myeloma, it serves as an important prognostic factor, where high levels often correlate with a greater tumor burden and more advanced disease. The marker is also utilized in chronic kidney disease, where elevated levels may indicate reduced filtration capacity. The combination of B2M and other laboratory values helps physicians evaluate both cancer progression and kidney function.
Why is a Beta-2-microglobulin test performed?
A blood test for B2M is used to assess certain blood cancers, including multiple myeloma, lymphoma, and chronic lymphocytic leukemia (CLL). Elevated levels of B2M can provide information about disease severity and progression. The marker is also used to evaluate kidney function, as reduced kidney filtration can lead to increased B2M levels in the blood.
When is a B2M test relevant?
The S-Beta-2-microglobulin blood test is primarily used in healthcare to monitor disease progression in blood cancers and assess kidney function. It is usually performed in consultation with a physician as part of a broader medical evaluation.
- Undergoing evaluation for blood cancer or requiring follow-up for a known diagnosis
- Experiencing fatigue, unexplained weight loss, fever, or recurrent infections – symptoms that may be associated with hematologic disorders
- Assessing kidney function in suspected or diagnosed kidney disease
Elevated levels of S-Beta-2-microglobulin (B2M) cannot be used alone to diagnose blood cancer. While high values may be observed in conditions such as multiple myeloma, lymphoma, and chronic lymphocytic leukemia (CLL), they can also be caused by other factors. Increased B2M levels can be seen in cases of inflammation, viral infections, or kidney dysfunction, particularly in chronic kidney disease, where B2M is not adequately filtered.
An abnormal test result does not necessarily indicate a serious illness and should always be interpreted in a broader clinical context. The treating physician will assess the results in conjunction with other laboratory values, clinical examinations, and the patient's medical history to ensure an accurate evaluation. Additional tests may be required to determine the cause of elevated B2M levels.
Reference Range for S-Beta-2-microglobulin
Reference values for S-Beta-2-microglobulin may vary between laboratories, but a common upper reference limit is
