Test ID: B2MU
Beta-2-Microglobulin (B-2-M), Urine
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
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
Automated Chemiluminescent Immunometric Assay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Beta 2 Microglobulin Test
Beta-2 Microglobulin, Urine
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Plastic, 10-mL urine tube (Supply T068)
Specimen Volume: 5 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 NaOH as preservative to the collection. This preservative is intended to achieve a pH of between approximately 6 and 8.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Frozen (preferred) | 14 days |
| Refrigerated | 48 hours |
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
Interpretation 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 1,000 times normal levels in cadmium-exposed workers.
Cautions 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. See Specimen Required for necessary collection requirements.
Clinical Reference Provides recommendations for further 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 (Epub 2002 Oct 29)
Method Description Describes how the test is performed and provides a method-specific reference
IMMULITE 2000 Beta-2 Microglobulin 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, Diagnostic Products Corporation, Los Angeles, CA PIL2KBM-15, 7/29/2008)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 3rd shift
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
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's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
82232
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| B2MU | Beta-2-Microglobulin, U | 1953-9 |
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