Urinary protein as measured with a pyrogallol red-molybdate complex, manually and in a Hitachi 726 automated analyzer

In this new method for determining urinary protein, the reaction is complete within 10 min at 37 degrees C. This method is applicable to automated as well as manual measurements. Protein concentration and absorbance at 600 nm are linearly related throughout a wide range of concentrations, 10 to 16 000 mg/L. However, the chromogenicity of the gamma-globulins in this method is 70% of that of albumin, as estimated from results by a biuret method. Within-run CVs were less than 3.3%; the day-to-day CV was 2.9%. Errors due to interfering components in urine are less than 2%. The normal range for urinary protein as measured by this method was from 28 to 141 mg/day. Results by this method (y) and by a trichloroacetic acid-biuret method (x) correlated well (n = 80, r = 0.995; y = 0.99x - 2.9).