Reference glomerular filtration rate levels in Japanese children: using the creatinine and cystatin C based estimated glomerular filtration rate

The present study was performed to determine the reference values of glomerular filtration rate (GFR) in children by age using the new eGFR equations derived from serum creatinine (Cr) and cystatine C (cysC). A total of 1137 children (509 males and 628 females) between the ages of 3 months and 16 years presenting at our facilities between 2008 and 2009 without diseases affecting the renal function were included in this study as in our previous reports for reference values of serum Cr and cysC. We calculated eGFR with the Cr based equation in children aged 2-16 years, and with the cysC based equation in those aged 3-23 months, and determined the reference values of GFR in Japanese children by each age group. We reviewed the median, 2.5 and 97.5 percentile of GFR reference value in each age group. The medians of reference GFRs are 91.7, 98.5, 106.3, and 113.1 mL/min/1.73 m(2) in children aged 3-5, 6-11, 12-17, and 18 months-16 years, respectively. We determined the normal reference values of GFR in children. It is important for pediatricians who examine pediatric chronic kidney disease patients to know the values of normal renal function.