Background: As there have been few studies conducted on children or adolescents, the purpose of this study was evaluate the relationship between single voided urine protein/creatinine (Up/Ucr) ratio and 24-hour urine protein excretion rate (PER), especially among children and adolescents in Taiwan.
Methods: After multistage random sampling, we collected 1,072 fasting single voided urine samples and 125 24-hour urine samples from seven- to 18-year-old students in Taiwan. We calculated the Up/Ucr of single voided urine samples and the 24-hour PER in urine.
Results: The mean value and the 95th percentile of the fasting single voided urine Up/Ucr ratio were 0.118 and 0.235, respectively. The mean value and the 95th percentile of the 24-hour PER were 3.61 and 5.66 mg/h/m2, respectively. There was no significant difference in Up/Ucr ratio between boys and girls. Up/Ucr ratio decreased significantly as age increased. The fasting single voided Up/Ucr ratio was highly correlated with 24-hour PER, with r2 = 0.95 (p < 0.001).
Conclusions: Fasting single voided Up/Ucr ratio is a good marker of 24-hour PER. It is also a simple, easy, convenient and speedy method to measure Up excretion. The single voided Up/Ucr ratio may also serve as a reference for the clinical diagnosis of Up excretion among normal subjects.