title: Cystatin C-based equation for estimating glomerular filtration rate in Japanese children and adolescents.
abstract: BACKGROUND
  Renal inulin clearance is the gold standard for evaluation of kidney function, but is compromised by problems of collecting urine samples in children, especially those <6 years or with a bladder dysfunction. Therefore, we should utilize the serum cystatin C (cysC)-based estimated glomerular filtration rate (eGFR) for measuring serum cysC. The purpose of the present study is to determine the applicability of the new serum cysC-based eGFR in Japanese children and adolescents, including infants with chronic kidney disease (CKD), for evaluation of renal function.
  
  
  METHODS
  Inulin clearance and standardized serum cysC level determined by the colloidal gold immunoassay were measured in 135 pediatric CKD patients between the ages of 1 month and 18 years with no underlying disease that affects renal function except CKD, to determine serum cysC-based eGFR in Japanese children and adolescents.
  
  
  RESULTS
  We showed the inulin clearance by expression of 1/serum cysC in pediatric CKD patients, which resulted in the equation: inulin GFR (mL/min/1.73 m(2)) = 104.1 × 1/serum cysC (mg/L) - 7.80. We also validated the cysC-based eGFR formula for Japanese adults. eGFR values obtained with the adult formula significantly underestimated GFR by approximately 8 % in children with CKD.
  
  
  CONCLUSIONS
  We determined the new cysC-based eGFR formula is useful for clinical screening of renal function in Japanese children and adolescents, including infants.
authors.affiliation: The Japanese Society for Pediatric Nephrology, the Committee of Measures for Pediatric CKD, Tokyo, Japan, o_uemura@hkg.odn.ne.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Uemura
authors.forename: Takuhito
authors.initials: T
authors.lastname: Nagai
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishikura
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hataya
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Gotoh
authors.forename: Naoya
authors.initials: N
authors.lastname: Fujita
authors.forename: Yuko
authors.initials: Y
authors.lastname: Akioka
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Kaneko
authors.forename: Masataka
authors.initials: M
authors.lastname: Honda
mesh_terms: D000293:Adolescent; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D008297:Male
chemical_list: D055316:Cystatin C