Beta-2 Microglobulin, Urine

Clinical Significance

Beta-2-Microglobulin, Urine - Beta-2-Microglobulin (B2M) is a low molecular weight protein that forms the light chain component of the histocompatibility antigen. It is synthesized by all nucleated cell types. It is an integral part of the class I MHC antigens and is present in all body fluids. B2M is filtered through the glomeruli of the kidney and is then reabsorbed and catabolized by the proximal tubular cells. In normal patients only trace amounts of B2M appear in the urine. Elevated urine B2M is seen in tubulo-interstitial disorders. Increased urine B2M is seen in cadmium exposure, diatrizoate, exercise, fever, nephrectomy, semen. There is evidence that monitoring B2M levels in HIV-infected individuals offers an independent predictor of progression to AIDS, leukemia and lymphoma

Patient Preparation

Patient should void bladder, then drink at least 500 mL of water before submitting specimen.

Specimen Requirements

10.0 mL Urine in a Beta-2 Plastic Vial

Alternate Specimen

 

TransportAndStorage

5 days Ambient (transport)
15 days Refrigerated
30 days Frozen

Collection Instructions

1. Patient should void bladder, then drink at least 500 mL (approximately 17 oz) of water. 
2. A urine sample should be collected within 1 hour. 
3. Pour exactly 10 mL of random urine into a Quest Diagnostics Beta-2 Microglobulin Transport Tube (#179979 available through Client Supply). 
4. Ship refrigerated. 
5. Alternatively, if the collection tubes are not available, pH the specimen to between 6 and 8 using 1N NaOH prior to shipping.

Beta-2 Microglobulin in urine is unstable in acidic urine (less than pH 6). Exactly 10 mL of urine in the Quest Diagnostics Beta-2 Microglobulin Transport Tube is required to achieve the required pH of between 6 and 8. Any volume above or below 10 mL will result in a pH that is outside the acceptable range.

Minimum Volume

10.0 mL Urine

Neonatal Volumne

Reference Range:

<18 Years	Not established
Adults	≤0.20 mg/L

Methodology:

• Immunoturbidimetric

Clinical Significance

Beta-2-Microglobulin, Urine - Beta-2-Microglobulin (B2M) is a low molecular weight protein that forms the light chain component of the histocompatibility antigen. It is synthesized by all nucleated cell types. It is an integral part of the class I MHC antigens and is present in all body fluids. B2M is filtered through the glomeruli of the kidney and is then reabsorbed and catabolized by the proximal tubular cells. In normal patients only trace amounts of B2M appear in the urine. Elevated urine B2M is seen in tubulo-interstitial disorders. Increased urine B2M is seen in cadmium exposure, diatrizoate, exercise, fever, nephrectomy, semen. There is evidence that monitoring B2M levels in HIV-infected individuals offers an independent predictor of progression to AIDS, leukemia and lymphoma

CDM

00910432

CPT Coding

82232 (code 81050 may be added at an additional charge for volume measurement)

Medical Necessity May Apply