EVALUATION OF AN AUTOMATED PYROGALLOL RED-MOLYBDATE METHOD FOR THE MEASUREMENT OF URINARY PROTEIN IN RATS

Methods for quantitating urinary protein differ in their ranges of lin earity, technical ease of performance, and applicability to automated analyzers. The Coomassie Brilliant Blue method is widely used but has limited linearity and its tendency to stain glassware has limited its application to automated analyzers. We evaluated a pyrogallol red-moly bdate protein dye-binding method (Biotrol USA, Inc.) on a Hitachi 705 analyzer for the quantitation of urinary protein in rats. This method showed a wide range of linearity (up to 2.6 g/l) and good precision. W ithin-run CVs of 6.6% and 1.3% and between-day CVs of 10.9% and 1.1% w ere observed at mean protein concentrations of 0.16 g/l and 1.96 g/l, respectively. In addition, rat urine protein results from this method correlated well (r(2) = 0.998, n = 40) with a Coomassie Brilliant Blue method (QuanTtest(TM) Blue, Quantimetrix Corporation). No significant or unexpected interferences were encountered with this method. We con clude that the automated pyrogallol red-molybdate method is an accepta ble and practical alternative to the Coomassie Brilliant Blue method f or the quantitation of urine protein in rats.