[Evaluation of glomerular filtration rate in children--serum markers and prediction equations].
BACKGROUND
In children, determination of glomerular filtration rate(GFR) is not easy, because serum creatinine (CRE) level changes by their growth and collection of urine is difficult. In this study, we evaluated serum GFR markers and prediction equations of GFR.


METHODS
Serum samples were obtained from 200 healthy children; 100 children aged 9 to 10 years and 100 children aged 12 to 13 years (50 males and 50 females respectively). Serum levels of three GFR markers i.e., CRE, cystatin C, and beta2-microglobulin (beta2mG) were measured, and prediction equations of GFR were calculated. Another 110 serum samples were obtained from children aged 0 to 16 years, and the same three markers were measured.


RESULTS
In comparing healthy children aged 9 to 10 years and 12 to 13 years, serum CRE levels were significantly higher in the latter group. Serum cystatin C levels were not different between these two groups. Although serum levels of CRE, cystatin C, and beta2mG were not significantly different between males and females aged 9 to 10 years, significantly higher levels of these three markers were observed in males than females aged 12 to 13 years. The reference values of cystatin C and CRE were < or = 0.760 mg/l, < or = 0.623 mg/dl in children aged 9 to 10 years, and < or = 0.835 mg/l, < or = 0.785 mg/dl in children aged 12 to 13 years. Investigation of serum samples obtained from children aged 0 to 16 years suggested the better utility of cystatin C as a GFR marker compared to CRE. The Shwartz prediction equation is considered to be useful among the three CRE-based prediction equations, while the Rule prediction equation is considered to be useful among the three cystatin C-based prediction equations.


CONCLUSIONS
We need the reference value of serum CRE in each age and gender to evaluate GFR. And we concluded serum cystatin C is the better GFR marker than CRE in children. As to the prediction equations, the Shwartz and the Rule prediction equation are considered to be practically useful in children.
Nakai
Keiko
K
Department of Laboratory Medicine, Iwate Medical University, Morioka, Japan. keikoyn@iwate-med.ac.jp
Kikuchi
Masayuki
M
Koyamaa
Tomiko
T
Saito
Kensuke
K
Suwabe
Akira
A
D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002648:Child; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values
D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine