[Usefulness of determining beta-2-microglobulin in serum and urine in patients with metabolically active kidney calculi and healthy individuals].
The study aimed at evaluating the proximal tubule function in patients with active metabolic urolithiasis with the assay of beta 2-microglobulin in the urine. The studies involved 30 patients with urolithiasis associated with chronic pyelonephritis and 31 patients with urolithiasis without pyelonephritis. Fifty healthy individuals served as a control group. Serum and urine beta 2-microglobulin concentrations were assayed with radioimmunological technique in all persons. Clearance of this microglobulin and tubular reabsorption were calculated. It was found that beta 2-microglobulin excretion with the urine is significantly higher in patients with metabolically active urolithiasis accompanied by the chronic pyelonephritis. beta 2-microglobulin clearance was significantly higher and tubular reabsorption significantly lower than those in patients without pyelonephritis and in control group. These finding suggest a dysfunction of the proximal tubule in patients with urolithiasis produced by the chronic inflammatory process in the urinary system. Negative correlation between blood serum beta 2-microglobulin levels and creatinine clearance was shown. Therefore, serum beta 2-microglobulin concentrations may be of value in evaluation of the glomerular filtration rate.