title: Beta-2 microglobulin-based equation for estimating glomerular filtration rates in Japanese children and adolescents.
abstract: BACKGROUND
  Although the creatinine (Cr)-based equation is widely used for estimating glomerular filtration rate (GFR), this equation is not ideally suited for children with low body weight or aged <2 years. Therefore, we established a new equation using serum beta-2 microglobulin (β2MG) levels for Japanese children with chronic kidney disease (CKD).
  
  
  METHODS
  Inulin clearance and standardized serum β2MG and Cr levels were measured in 137 CKD patients aged 1 month-18 years. Using the previously established normal β2MG levels, Cr reference values, and Cr-based equation of estimated GFR (eGFR) in Japanese children, receiver operating characteristics (ROC) analyses were performed to compare the diagnostic accuracy between β2MG- and Cr-based estimations of GFR.
  
  
  RESULTS
  Serum β2MG concentrations progressively increased as GFRs reduced. The correlation coefficients between GFR and β2MG, and between GFR and 1/β2MG were -0.74 (p < 0.001) and 0.86 (p < 0.001), respectively. The inulin clearance, as based on 1/serum β2MG expression, in pediatric CKD patients resulted in the equation: inulin GFR (mL/min/1.73 m(2)) = 149.0 × 1/serum β2MG (mg/L) +9.15. ROC analyses indicated that the ability of serum β2MG-based GFR <95 mL/min/1.73 m(2) in children >2 years was better than the Cr-based estimated GFR (areas under the ROC curve 0.960 vs. 0.948, respectively).
  
  
  CONCLUSIONS
  The new β2MG-based eGFR formula is useful for clinical screening of renal function in Japanese children and adolescents, and measurement of serum β2MG and Cr levels as markers for predicting glomerular function may aid the early detection of mildly reduced GFR in this population.
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan. ikezumi@med.niigata-u.ac.jp.|Department of Pediatrics, Niigata University Medical and Dental Hospital, Asahimachi-dori, Niigata, 951-8510, Japan. ikezumi@med.niigata-u.ac.jp.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Ikezumi
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Uemura
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Takuhito
authors.initials: T
authors.lastname: Nagai
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishikura
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Ito
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hataya
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Fujita
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Akioka
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Kazumoto
authors.initials: K
authors.lastname: Iijima
authors.affiliation: The Committee of Measures for Pediatric CKD, The Japanese Society for Pediatric Nephrology, Tokyo, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Honda
mesh_terms: D000293:Adolescent; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007444:Inulin / Q000378:metabolism*; D007564:Japan; D007677:Kidney Function Tests; D008297:Male; D055641:Mathematical Concepts; D012372:ROC Curve; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000503:physiopathology; D001613:beta 2-Microglobulin / Q000097:blood*
chemical_list: D001613:beta 2-Microglobulin; D007444:Inulin; D003404:Creatinine
keywords: Beta-2 microglobulin-based equation; Children; Chronic kidney disease; Estimated glomerular filtration rate; Kidney function
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