Specimen Collection Manual and Test Catalog

10 mL, (minimum 10 mL) random urine

*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 of urine above or below 10 mL will result in a pH that is outside the acceptable range.

Patient should void bladder, then drink at least 500 mL (approximately 17 oz) of water before submitting specimen. Sample should be collected within one hour from the time the patient drinks the water.

Pour exactly 10 mL of random urine into a "Quest Diagnostics Beta-2 Microglobulin Transport Tube." Cap and invert tube. Alternatively, if the collection tubes are not available, pH the 10 mL specimen to between 6 and 8 using 1N NaOH prior to shipping.

Refrigerated.

Room Temperature: 5 days. Refrigerated: 15 days. Frozen: 30 days.

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

Beta 2 microglobulin, urine.

Quest test code 49448, B2MG

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.