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Test Code B2M; SQ: BETA2 Beta-2-Microglobulin, Serum

Reporting Name

Beta-2-Microglobulin, S

Useful For

Prognosis assessment of multiple myeloma

 

Evaluation of renal tubular disorders

Testing Algorithm

For more information, see Multiple Myeloma: Laboratory Screening

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  14 days

Reference Values

1.21-2.70 mcg/mL

Day(s) Performed

Monday through Friday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82232

LOINC Code Information

Test ID Test Order Name Order LOINC Value
B2M Beta-2-Microglobulin, S 1952-1

 

Result ID Test Result Name Result LOINC Value
B2M Beta-2-Microglobulin, S 1952-1

Clinical Information

Beta-2-microglobulin (beta-2-M) is a small membrane protein (11,800 Da) associated with the heavy chains of class I major histocompatibility complex proteins and is, therefore, on the surface of all nucleated cells. The small size allows beta-2-M to pass through the glomerular membrane, but it is almost completely reabsorbed in the proximal tubules.

 

Serum beta-2-M levels are elevated in diseases associated with increased cell turnover. Levels are also elevated in several benign conditions such as chronic inflammation, liver disease, kidney dysfunction, some acute viral infections, and a number of malignancies, especially hematologic malignancies associated with the B-lymphocyte lineage.

 

In multiple myeloma, beta-2-M is a powerful prognostic factor, and values less than4 mcg/mL are considered a good prognostic factor.

 

In renal tubular disease, serum levels are low and urine levels are high. Although urine beta-2-M has been used to assess tubular dysfunction, it is not stable in urine below pH 5.5.

 

For more information see Multiple Myeloma: Laboratory Screening

Interpretation

A serum beta-2-microglobulin (beta-2-M) value of less than 4 mcg/mL is a good prognostic factor in patients with multiple myeloma. In a study of pretreatment serum beta-2-M levels in 100 patients with myeloma, it was reported that the median survival of patients with values greater than 4 mcg/mL was 12 months, whereas median survival for patients with values less than 4 mcg/mL was 43 months.

Method Description

Concentrations of beta-2-microglobulin are determined by nephelometry.(Instruction manual: Siemens Nephelometer II Operations. Siemens, Inc., Newark, DE)

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Method Name

Nephelometry

Forms

If not ordering electronically, complete, print, and send Renal Diagnostics Test Request (T830)

Secondary ID

9234