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EPIC CODE: LAB2150 Beta-2 Microglobulin, Random, Urine

Additional Codes

Sunquest:   B2MGUM
Mayo:          B2MU
Previously:  ARUP 0080432

Specimen Required

Patient Preparation: For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Container/Tube: Plastic, urine tube

Specimen Volume: 3 mL

Collection Instructions:

1. Patient should empty bladder.

2. Have patient drink at least 0.5 liters of water.

3. Within 1 hour, collect a random urine specimen.

4. Add 1 M sodium hydroxide (NaOH) as preservative to the collection. This preservative is intended to achieve a pH of between approximately 6 and 8.

Secondary ID


Useful For

Evaluation of renal tubular damage


Monitoring exposure to cadmium and mercury

Method Name

Automated Chemiluminescent Immunometric Assay

Reporting Name

Beta-2 Microglobulin, U

Specimen Type


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 14 days
  Refrigerated  48 hours

Reject Due To

Specimen with pH <6 Reject

Clinical Information

Beta-2 microglobulin is a low-molecular-weight protein that forms the light chain component of class I histocompatibility (HLA: human leukocyte antigen) antigens.


Increased urine levels are seen in proximal tubular renal damage due to a variety of causes, including cadmium, mercury, lithium, or aminoglycoside toxicity; pyelonephritis; and Balkan nephropathy, a chronic interstitial nephritis of unknown etiology.

Reference Values

≤300 mcg/L


Increased excretion is consistent with renal tubular damage.


Beta-2 microglobulin excretion is increased 100 to 1000 times normal levels in cadmium-exposed workers.


Degradation of beta-2 microglobulin occurs at pH <6.0.

Clinical Reference

1. Ikeda M, Ezaki T, Tsukahara T, et al: Threshold levels of urinary cadmium in relation to increases in urinary beta2-microglobulin among general Japanese populations. Toxicol Lett. 2003 Feb 3;137(3):135-141

2. Moriguchi J, Ezaki T, Tsukahara T, et al: Comparative evaluation of four urinary tubular dysfunction markers, with special references to the effects of aging and correction for creatinine concentration. Toxicol Lett. 2003 Aug 28;143(3):279-290

3. Stefanovic V, Cukuranovic R, Mitic-Zlatkovic M, Hall PW: Increased urinary albumin excretion in children from families with Balkan nephropathy. Pediatr Nephrol. 2002 Nov;17(11):913-916

Method Description

Testing is performed on the Immulite 2000. The Immulite 2000 Beta-2 Microglobulin assay is a solid phase, 2-site chemiluminescent enzyme-labeled immunometric assay. The solid-phase bead is coated with an affinity-purified murine monoclonal anti-beta-2 antibody. The serum sample and alkaline phosphatase conjugated affinity-purified goat polyclonal anti-beta-2 antibody are incubated to bind beta-2 microglobulin into an antibody sandwich complex.


The chemiluminescent substrate, a phosphate ester of adamantyl dioxetane, in the presence of alkaline phosphatase produces light proportional to the concentration of the beta-2 microglobulin in the sample.(Package insert: IMMULITE 2000 Beta-2 Microglobulin. Siemens Healthcare Diagnostics; 11/05/2012)

Day(s) Performed

Monday, Wednesday, Friday

Report Available

1 to 3 days

Specimen Retention Time

3 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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


LOINC Code Information

Test ID Test Order Name Order LOINC Value
B2MU Beta-2 Microglobulin, U 1953-9


Result ID Test Result Name Result LOINC Value
B2MU Beta-2 Microglobulin, U 1953-9

NY State Approved



If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.