Beta-2-Microglobulin, Random Urine (UBETA)

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

LAB2077

4944

UBETA

CPT code 81050 may be added at an additional charge for volume measurement

10 mL random urine collected in a Quest Diagnostics Beta-2 Microglobulin Transport Tube (available through client supply)

10 mL

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 (available through Client Supply).
4. Ship room temperature.
5. Alternatively, if the collection tubes are not available, pH the specimen must be adjusted 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.

Plastic screw-cap vial
Kennestone nursing: call lab for instructions regarding collection and transport.

Room temperature

Room temperature: 5 days
Refrigerated: 15days
Frozen: 30 days

Specimens received in a non-Beta-2 Microglobulin transport tube with a pH less than 6 • Any volume other than 10 mL urine in the transport tube • Any specimen with pH less than 6

2 days

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 catabolised 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.