Alpha-1-Mikroglobulin in Urin und Serum bei Proteinurie und Niereninsuffizienz

Publisher Website
Google Scholar
Abstract
Alpha-1-microglobulin (alpha-1-m) is a low molecular weight glycoprotein (mw 25–33 KD) that is filtered through the glomeruli and reabsorbed in the proximal parts of the renal tubules where it is catabolized. Normal ranges were established for alpha-1-m (100 healthy controls) in serum (20–42 mg/l) and urine (3.5–8 mg/l). Alpha-1-m was then measured in 341 urine samples whose protein pattern had been classified as “pathologic” and “normal” according to microelectrophoresis. Increased alpha-1-m concentrations were found in 266 out of 280 pathologic urines (5% false negative) and in 3 out of 61 normal urines (4% false positive). Beta-2-microglobulin (beta-2-m), total protein or protein test strips showed a poorer correlation to the electrophoretic results. Measurement of alpha-1-m is, therefore, the most sensitive of these methods for the detection of proteinuria. In 90 patients with low molecular weight proteinuria and either with or without renal insufficiency alpha-1-m concentrations were determined in both urine and serum. While all patients had elevated urinary alpha-1-m concentrations, increased serum values were only found in renal insufficiency (Ccreacrea <70 ml/min). Pathologic alpha-1-m concentrations therefore only allow the conclusion of isolated tubular impairment when the GFR is greater than 70 ml/min. Data from 350 patients with various renal and hypertensive diseases showed that serum alpha-1-m is a more sensitive indicator of renal insufficiency, even in the so-called “creatinine blind” range (60–100 ml/min) of the GFR than either creatinine or beta-2-m.