Correlation between Total Urinary Protein Quantitation and Random Urine Sample Protein/Creatinine Ratio in Children

Abstract

Random urine samples and 24-hour urine samples were obtained prospectively from 5 healthy children and 28 children with renal diseases, aged 2 to 14 years. The relationship between the random urine protein/ creatinine ratio (Up/Ucr) and total daily protein excretion were studied. Protein concentrations were measured using a Coomassie blue binding technique. The Up/Ucr measured in 61 urine samples correlated closely with 24-hour urine protein excretion. In log-transformed data, the correlation was linear with a coefficient of 0.97 (log Up/Ucr mg/mmole = 0.786 + 1. 018 logTP, TP in mg/h/M2). The Up/Ucr that coincided with a protein excretion of 4 mg/h/M2 was 25.1 mg/mmole (0.222 mg/ mg) and of 40 mg/h/M2 was 261 mg/mmole (2.31 mg/mg). The results of our study indicate that Up/ Ucr is an accurate estimate of quantitative protein excretion. In clinical practice this is a suitable method of quantification for proteinuria in patients with renal disease.