Urinary beta 2 microglobulin in upper and lower urinary-tract infections.

Beta 2-- microglobulin excretion in 24 h urine collections and beta2- microglobulin clearance were significantly increased in patients with upper-urinary-tract infections, but beta 2- microglobulin clearance and excretion were normal in patients with cystitis. Beta 2-microglobulin estimation may be used to distinguish between upper and lower urinary-tract infections, except when pre-existing tubular damage is present. Voided urine must have a pH above 6 . 0, since beta 2- microglobulin is rapidly degraded in the bladder at low pH.