B2MU - Overview: Beta-2 Microglobulin, Random, Urine (2023)

Useful For

Suggests clinical disorders or settings where the test may be helpful

Evaluation of renal tubular damage

Monitoring exposure to cadmium and mercury

Method Name

A short description of the method used to perform the test


NY State Available

Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name

Lists a shorter or abbreviated version of the Published Name for a test

Beta-2 Microglobulin, U


Lists additional common names for a test, as an aid in searching

Beta 2 Microglobulin Test

Beta-2 Microglobulin, Urine

B2M, (Beta-2 Microglobulin) Urine

Specimen Type

Describes the specimen type validated for testing


Specimen Required

Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.


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

Specimen Minimum Volume

Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

1 mL

Reject Due To

Identifies specimen types and conditions that may cause the specimen to be rejected

Specimen with pH <6 Reject

Specimen Stability Information

Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

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

Useful For

Suggests clinical disorders or settings where the test may be helpful

Evaluation of renal tubular damage

Monitoring exposure to cadmium and mercury

Clinical Information

Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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

Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

< or =300 mcg/L


Provides information to assist in interpretation of the test results

Increased excretion is consistent with renal tubular damage.

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


Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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

Clinical Reference

Recommendations for in-depth reading of a clinical nature

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

Describes how the test is performed and provides a method-specific reference

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)

PDF Report

Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed

Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday, Wednesday, Friday

Report Available

The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 3 days

Specimen Retention Time

Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

3 months

Performing Laboratory Location

Indicates the location of the laboratory that performs the test



Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification

Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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

Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information

Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

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

Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.

B2MU Beta-2 Microglobulin, U 1953-9

Test Setup Resources

Setup Files

Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | PHP Pdf | CMS Pdf

Sample Reports

Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports

International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports


What is the normal range of B2M in urine? ›

Normal findings : Blood: 0.70-1.80 mcg/mL. Urine: ≤300 mcg/L.

What is a beta-2 microglobulin test for urine? ›

What is a beta-2 microglobulin tumor marker test? A beta-2 microglobulin tumor marker test measures the amount of a protein called beta-2 microglobulin (B2M) in your body fluids. The test usually uses a sample of your blood. It may also be done using urine (pee) or in rare cases cerebrospinal fluid (CSF).

What is considered a high B2M level? ›

High B2M levels (>2.9 mg/dl) could identify a group of patients with an adverse outcome within patients in stage I disease (P = 0.02).

What is beta-2 microglobulin B2M indicative in case of? ›

For the diagnosis of multiple myeloma, the serum β2-microglobulin level is one of the prognostic factors incorporated into the International Staging System. The serum β2-microglobulin level is elevated (>2.7 mg/L) in 75% of patients at the time of diagnosis. Patients with high values have inferior survival.

What is too high beta-2 microglobulin? ›

What does it mean if your Beta-2 Microglobulin, Serum result is too high? Elevated concentration levels of beta-2 microglobulin is attributed to diseases with a high cell turnover. It is a powerful prognosis factor for multiple myeloma, a type of bone marrow cancer.

What is the beta-2 microglobulin level for multiple myeloma? ›

The International Staging System for Multiple Myeloma

Stage 1 – Serum beta-2 microglobulin level measuring less than 3.5 (mg/L) with an albumin level measuring 3.5 (g/dL) or greater.

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