[Simplified determination of proteinuria in children using a single urine sample]

In children and adolescents the evaluation of proteinuria is cumbersome because of the need to obtain timed urine collections. The protein/creatinine ratio (using a Coomassie blue binding technique and a kinetic Jaffe reaction, respectively) measured in 134 pediatric patients with renal disease aged 2 months to 16 years correlated closely with the overnight urine protein excretion rates using the statistical approach suggested by Bland and Altman to compare methods of measuring some quantity. The upper limit of urinary protein/creatinine ratio measured in 252 healthy children and adolescents aged 4 to 19 years was shown to be 19 mg/mmol. No age-related differences in urinary protein excretion were noted in healthy subjects. The random urine protein/creatinine ratio provides an accurate assessment of quantitative protein excretion and avoids errors and difficulties associated with timed urine collection.