Osamu Uemura1,2, Takuhito Nagai3, Satoshi Yamakawa3, Tetsuji Kaneko4, Yoshiko Hibi3, Yasuhito Yamasaki3, Masaki Yamamoto3, Masaru Nakano3, Naoyuki Iwata3, Satoshi Hibino3. 1. Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, 426 7-chome, Morioka-cho, Obu, Aichi, 474-8710, Japan. o_uemura@hkg.odn.ne.jp. 2. Department of Clinical Medicine, Japanese Red Cross Toyota College of Nursing, 12-33 Nanamagari, Hakusan-cho, Toyota, Aichi, 471-8565, Japan. o_uemura@hkg.odn.ne.jp. 3. Department of Pediatric Nephrology, Aichi Children's Health and Medical Center, 426 7-chome, Morioka-cho, Obu, Aichi, 474-8710, Japan. 4. Department of Clinical Research, Tokyo Metropolitan Children's Medical Center, 2-8-29 Musashidai, Fuchu, Tokyo, 183-8561, Japan.
Abstract
BACKGROUND: Although renal inulin clearance (Cin) is the gold standard for evaluation of kidney function, it cannot be measured easily. Therefore, creatinine clearance (Ccr) is often used clinically to evaluate kidney function. Enzymatically measured Ccr was recently found to be much higher than Cin because of the tubular secretion of creatinine (Cr). This study compared three measures of renal clearance, inulin, 2-h Ccr, and 24-h Ccr, in children. METHODS: Kidney function was evaluated in 76 children (51 males and 25 females) aged 1 month to 18 years with chronic kidney disease (CKD) by three renal clearance methods at almost the same time. RESULTS: Correlations between each pair of three renal clearance measurements were determined. Approximate glomerular filtration rate (GFR) was equal to 62 % of 2-h Ccr or 76 % of 24-h Ccr. CONCLUSION: Cr secretion by renal tubules was approximately 50 % of the GFR. In this study, we indicate that the measurements of 2-h Ccr or 24-h Ccr do not show true GFR but we could infer approximate GFR from the values. The use of 2- or 24-h Ccr might contribute to the treatment of pediatric CKD patients.
BACKGROUND: Although renal inulin clearance (Cin) is the gold standard for evaluation of kidney function, it cannot be measured easily. Therefore, creatinine clearance (Ccr) is often used clinically to evaluate kidney function. Enzymatically measured Ccr was recently found to be much higher than Cin because of the tubular secretion of creatinine (Cr). This study compared three measures of renal clearance, inulin, 2-h Ccr, and 24-h Ccr, in children. METHODS: Kidney function was evaluated in 76 children (51 males and 25 females) aged 1 month to 18 years with chronic kidney disease (CKD) by three renal clearance methods at almost the same time. RESULTS: Correlations between each pair of three renal clearance measurements were determined. Approximate glomerular filtration rate (GFR) was equal to 62 % of 2-h Ccr or 76 % of 24-h Ccr. CONCLUSION:Cr secretion by renal tubules was approximately 50 % of the GFR. In this study, we indicate that the measurements of 2-h Ccr or 24-h Ccr do not show true GFR but we could infer approximate GFR from the values. The use of 2- or 24-h Ccr might contribute to the treatment of pediatric CKDpatients.