The Factors Affecting Accurate Quantitaion of Proteinuria Using Spot Urine Protein/Creatinine Ratio in Children

PURPOSE: Many results have reported a correlation between the spot urine protein/creatinine ratio(P/C ratio) and 24-hour urinary protein(24UP) amount. This study was designed to evaluated correlation between 24UP amounts and P/C ratio in children and to find the factors that affect this correlation. METHODS: 210 patients who visited the Department of Pediatrics in Busan Paik Hospital from september 2003 to december 2007 were included in this study. All the patients were divided into I, II, III/A, B, C group[I:24UP(mg/m2/day)] or =1,000, A: Cr excretion(mg/kg) or =25)]. Pearson correlation analysis was performed between 24UP and P/C ratio to evaluate the relationship. We defined fractional difference between 24UP and P/C ratio, and then performed multiple regression analysis. RESULTS: There was a strong positive linear correlation between 24UP and P/C ratio in all patients, and the correlation was also good in each group. The factors affecting accurate quantitation of proteinuria using spot urine P/C ratio was creatinine excretion. CONCLUSION: Spot urine P/C ratio is a useful test to predict proteinuria roughly. Therefore, we expect that urine P/C ratio can be used as parameter instead of 24UP, if we set cutoff value of P/C ratio considered to creatinine excretion according to age and sex in large pediatric population.

The Usefulness of Spot Urine Protein/Creatinine Ratio in Evaluating Proteinuria in Children and the Correlation between 24-hour Urinary Protein Amount and Spot Urine Protein/Creatinine Ratio

PURPOSE: Recently, different results about factors affecting accurate quantitation of 24-hr urinary protein(24UP) amount using spot urine protein/creatinine ratio(PCR) have been reported. The current study was designed to evaluate correlation between 24UP amounts and PCR in children, and the effect of 24UP amounts, age, sex, and glomerular filtration rate(GFR) on this correlation. METHODS: Among 94 patients who visited the department of pediatrics in Busan Paik Hospital from March 2002 to August 2002, 68 patients whose urinary creatinine excretion was > or = 15 mg/kg/day were included in this study. All the patients were divided into I, II/A, B group(I : 24UP or = 500 mg/day, A : or = 10 years of age). Pearson correlation analysis was performed between 24UP and PCR to evaluate the relationship. We defined fractional difference between 24UP and PCR, and then performed multiple regression analysis with 24UP amount, age, GFR and fractional difference. RESULTS: There was a strong positive linear correlation between 24UP and PCR(R=0.936, P or = 500 mg. The factors affecting accurate quantitation of proteinuria using spot urine PCR was age, not 24UP amount, GFR or sex. CONCLUSION: Spot urine PCR is a useful test but has limitations in predicting 24UP amount. Therefore, it should be used only as screening method. Age-adjusted PCR cutoff values may be necessary to predict 24UP amount in children with proteinuria.