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Beta 2 Microglobulin, Urine

Test Codes

EPIC: LAB5951, Beaker: XB2MU, Mayo: B2MU

Department

Send Outs

Instructions

For Collection: Void the urinary bladder, then drink a large glass of water. Collect a urine specimen within one hour. Add 1 M NaOH as preservative to the collection. This preservative is intended to achieve a pH of between approximately 6 and 8.

Specimen Collection Criteria

Collect: Random urine specimen in a screw-capped container (preferred) or other sterile collection cup, as described in Instructions. (Minimum: 1.0 mL)

Physician Office/Draw Specimen Preparation

Freeze (-20°C/-4°F or below) the specimen prior to transport.

Preparation for Courier Transport

Transport: 3.0 mL urine, frozen (-20°C/-4°F or below). (Minimum: 1.0 mL)

Rejection Criteria

Specimens not collected and processed as indicated.

In-Lab Processing

If pH is greater than 8, lower pH to between 6-8 by adding 1M HCl. If pH less than 6, increase pH to 6-8 by adding 5% NaOH. Titrate with appropriate preservative until pH 6-8 has been reached. Please record the pH on the transport tube and test request form.

Transport: 3.0 mL urine, frozen (-20°C/-4°F or below) in a plastic transport tube. (Minimum: 1.0 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 48 hours
Frozen (-20°C/-4°F or below): 14 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday, Wednesday, Friday.
Results available in 1-3 days.

Reference Range

By report.

Test Methodology

Quantitative Chemiluminescent Immunoassay.

Interpretation

Human beta-2 microglobulin is a low molecular mass protein (11,800 daltons) consisting of a single polypeptide chain of 100 amino acids. The protein is present on the surface of nucleated cells as the "light chain associated with HLA."

In healthy subjects, beta-2 microglobulin is produced at a relatively constant rate. It is eliminated by the kidneys, where it is filtered, reabsorbed, and catabolized by the proximal tubules. Normally only trace amounts are found in the urine, however, if the proximal tubular cells are damaged by drugs, disease, heavy metals, etc., the urinary excretion rises.

Synthesis of beta-2 microglobulin is increased in patients with various malignant and immunological disorders (particularly lymphoma, leukemia, and multiple myeloma). The degree of elevation can be related to the tumor cell load, disease activity and prognosis.

Clinical Utility

This assay is used to evaluate renal disease and to monitor the activity of various malignant and hematological disorders.

CPT Codes

82232

Contacts

Last Updated

10/26/2023